Thursday

February 23, 2017
Number of results: 10,023

**math**

The mean score on a Math exam was 50% and the standard deviation was 10%. Assume the results were normally distributed. (a) What percent of students earned a score between 50% and 70%? (b) If 60 students took the exam, how many got a score between 50% and 70%?

*March 28, 2010 by kevin*

**AP Stats**

The mean weight of pears grown in a certain orchard is 6 ounces with a standard deviation of .5 ounces. A random sample of 30 pears is selected. What is the approximate probability that the sample mean weight is less than 5.5 ounces?

*April 25, 2010 by Lilly*

**math**

If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, what percentage of light bulbs have a life less than 2500 hours?

*April 2, 2012 by Bridget*

**statistics**

If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, what percentage of light bulbs have a life less than 2500 hours?

*May 26, 2013 by madonna*

**Statistics**

If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, what percentage of light bulbs have a life less than 2500 hours

*January 12, 2015 by Michael*

**MATH 2**

It is found that the number of raisins in a box of a popular cereal is normally distributed, with a mean of 133 raisins per box and a standard deviation of 10 raisins. My cereal box has 147 raisins. What is the z-score for this box of cereal?

*December 15, 2016 by James*

**MATH**

it is found that the number of raisins in a box of a popular cereal is normally distrubuted, with a mean of 133 raisins per box and a standard deviation of 10 raisins. my cereal box has 152 raisins, what is the z-score for this box of cereal?

*December 19, 2016 by JONES*

**Statistics**

The heights of 18-year-old men are approximately normally distributed with mean 68 inches and standard deviation 3 inches. What is the probability that the average height of a sample of ten 18-year-old men will be less than 70 inches? Round your answer to four decimal places. ...

*June 20, 2010 by alex*

**statistics**

A cell phone service provider has selected a random sample of 20 of its customers in an effort to estimate the mean number of minutes used per day. The results of the sample included a sample mean of 34.5 minutes and a sample standard deviation equal to 11.5 minutes. Based on ...

*February 22, 2015 by timothy kendricks*

**math**

if, instead of assuming that the mean body temperature is 98.20 degree Ferinheight, we assume that the mean is 98.60 F(as many people believe), wht is the chance of randomly selecting 106 people and getting a mean of 98.20 degree F or lower? (continue to assume that the ...

*September 25, 2016 by Anonymous*

**Statistics**

A manufacturer of a low-tar cigarette claims that their cigarettes contain an average of 16.3 mg of tar with a standard deviation of 3.1 mg per cigarette. How many sample cigarettes must the manufacturer observe to be 99% confident that the width of the confidence interval is ...

*February 12, 2012 by Angel*

**algebra homework check**

The monthly rents for the apartments in a Business building are listed below. $425, $550, $550, $550, $650, $650, $650, $650, $800, $900 Part A: Find the mean$637.50 median=$650 mode=$650 range=$475 and standard deviation of the rents???

*May 25, 2012 by jenny*

**Management**

The bulbs manufactured by a company gave a mean life of 3000 hours with standard deviation of 400 hours. If a bulb is selected at random, what is the probability it will have a mean life less than 2000 hours? Question: 1) Calculate the probability. 2) In what situation does ...

*March 28, 2013 by Rajan*

**fnu**

The average age of doctors in a certain hospital is 50.0 years old. Suppose the distribution of ages is normal and has a standard deviation of 4.0 years. If 16 doctors are chosen at random for a committee, find the probability that the average age of those doctors is less than...

*June 10, 2014 by giovanny*

**statistics**

The average age of doctors in certain hospital is 43 years old. Suppose distribution of ages is normal and the standard deviation is 8.0 years. If 25 doctors is chosen at random for a committee, find the probability the average age for those doctors is less than 43.8 years. ...

*March 11, 2015 by stuart joel*

**statistics**

we want to if men and women perform differently on statistics tests. The average of 15 men's scores was 76. The average of 10 women's scores was 83. The standard deviation in both cases is 10. Test at 5% significance level. what is the null and alternate hypothese? is it a one...

*February 26, 2010 by Anonymous*

**statistics**

A charity believes that when it puts out an appeal for charitable donations the donations it receives will normally distributed with a mean of $50 and standard deviation of $6, and it is assumed that donations will be independent of each other. (i) Find the probability that a ...

*February 15, 2011 by Probability*

**statistics**

calculate the correlation for data set A. Data Set A: xi = 65, 55, 50, 45, 35 yi= 44, 52, 68, 20, 36 I know how to find the mean, variance, standard deviation, and z-score. The part I am having trouble finding is the ZxiZyi. In the chart that I have to fill in it says Zxi in ...

*July 6, 2011 by Hannah*

**Stats....how do i do this??**

SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of about 100 points, and are approximately normally distributed. What SAT I score within the population would have a percentile rank of approximately 16? Im not sure how to do this...

*October 18, 2011 by Jen*

**statistics**

Assume that women's heights are normally distributed with a mean=63.6 in. and standard deviation = 2.5 in. a) To be eligible for the US Marine Corps, a woman must have a height between 58 in. and 73 in. Find the percentage of women who satisfy that requirement. b)If the ...

*July 29, 2012 by jimmy*

**Algebra 2**

Times for an ambulance to respond to a medical emergency in a certain town are normally distributed with a mean of 450 seconds and a standard deviation of 50 seconds. Suppose there are 160 emergencies in that town. In about how many emergencies are the response times expected ...

*December 6, 2016 by Bella*

**Statistics**

Second Problem A. determine the mean, median, and the standard deviation B. Determine the coefficient of skewness using Pearson's method C. Determine the coefficient of skewness using the software method Commison earned($000)last year by the sales representatives at the ...

*September 12, 2007 by Jose*

**Math**

What is the difference between the height of the tallest man at 92.95" and the mean height of men at 69.6" and a stanard deviation of 2.8? How many standard deviations is that? Convert tallest man to a z score Does tall mans height meet the criterion of being unusual by ...

*January 23, 2011 by Help please!*

**statistics**

Boxes of bran flakes are known to be normally distributed with a mean weight of 475g and a standard deviation of 10g.Calculate the probability of a box having a weight exceeding 485 grams. Calculate the probability that the mean weight of sixteen boxes will exceed 480g.

*March 2, 2013 by Sue*

**statistics**

the weights of shells follow a normal distribution. a random sample of 12 hybrid shells a a mean weight of 1.7 pounds with standard deviation 0.24 pounds. Find a 95 % confidence interval level for the mean weight if the fall catch is within 0.1 pounds of the sample estimate

*March 21, 2013 by Lost37*

**statistics**

A study of the time spent shopping in a supermarket for a market basket of 20 specific items showed an approximately uniform distribution between 20 minutes and 40 minutes. What is the probability that the shopping rime will be a. Between 25 and 30 minutes? b. less than 35 ...

*November 19, 2013 by drea*

**statistics for health research**

the income of a group of 10,000 health system employees was found to be normally distributed with a mean=750 pm and standard deviation=50. show that of this group about 95% had income exceeding 668 and only 5% had income exceeding 832

*June 16, 2014 by maureen*

**Statistic**

A random sample of size 20 drawn from a normal distribution has a sample mean of 8 and a sample standard deviation of 4. A) Compute the sample test statistic t under the null hypothesis H_0: Mue(mean)=7 B) State the alternate hypothesis if you believe that the population mean ...

*December 4, 2014 by Yira f*

**statistics**

The physical plant at the main campus of a large state university receives daily requests to replace florecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 37 and a standard deviation of 3. Using the empirical rule (as presented...

*October 31, 2014 by Huong Nguyen*

**stats**

Scores on a test are approximately normally distributed with a mean of 70 and a standard deviation of 9. The teacher wants to give A’s to the top 10% of students, B’s to the next 25%, and C’s to the next 42%. a.) what is the bottom cutoff for a C grade? b.) what is the ...

*April 25, 2016 by vanessa*

**Bio**

im stuck on these questions for my study guide Please help! i don't want links. thanks 1. Which of the follwoing would be an appropriate measure of the phenotypic variation of a trait in a population? a) the mean of the trait in the population b) the standard deviation of the ...

*May 25, 2011 by Philip*

**statistics**

Assume the population distribution of FEV is normal with standard deviation 400 mLi. (a) find P(E) is n=15 and population mean is 2800 mLi (B) find P(E) is n=15 and the population mean is 2600mLi (C) How does P(E) depend on the population mean?

*October 13, 2009 by Sam*

**statistics**

Among coffee drinkers, men drink a mean of 2.8 cups per day with a standard deviation of 0.5 cups. Assume the number of drinking per day follows a normal distribution. What proportion drink 3 cups per day or more?

*February 20, 2012 by Bri*

**statitics**

Certain data includes 36 body temperatures for which the sample mean is equal to 98.20 °F and standard deviation of 0.62 °F. Using this sample statistics, construct a 95% confidence interval of the mean body temperature. What does the sample suggest about the use of 98.6°F ...

*May 19, 2014 by statitics*

**math**

No idea how to do this. I looked in my book and there usually is a data set present to get the first, second and third quartile. The lifetimes of lightbulbs of a particular type are normally distributed with a mean of 392 hours and a standard deviation of 9 hours. Find the ...

*April 22, 2007 by J*

**homework statistics**

Consider a random sample with sample mean x. If the sample size increased from n = 40 to n = 360, then the standard deviation of x will: a. remain the same b. increase by a factor of 9 (will be multiplied by 9) c. decrease by a factor of 9 (will be multiplied by 1/9) d. ...

*July 22, 2011 by Jackay 70*

**statistics**

Someone who has never seen a normal die before decides to estimate the mean value of all its faces (μ) by rolling it many times. First, they are told that the standard deviation is σ = 1.7. Then, they roll the die 50 times and get a sample mean of x-bar = 3.7. ...

*January 29, 2012 by Nadia*

**statistics probability**

Alice earned a score of 940 on an IQ test.The mean test score was 850 with a standard deviation of 100.(Assume that test scores are normally distributed). Q1a).What proportion of students had a higher score than alice? Qb)Find the score exceeded by 2.5% of the students.

*November 14, 2010 by koo*

**Stats**

Consider the following Hypotheses test: Ho:m>=80 Ha:m<80 A sample of 121 provided a sample mean of 77.3. The population Standard Deviation is known to be 16.5. A. compute the value of test statistic B. Determin the p value: and at 93.7% confidence, Test the above ...

*April 29, 2012 by bobbie*

**statistics**

A vending machine is designed to dispense a mean of 7.6 oz of coffee into an 8-oz cup. If the standard deviation of the amount of coffee dispensed is 0.4 oz and the amount is normally distributed, find the percent of times the machine will a) dispense less than 7.0 oz. b) ...

*November 20, 2012 by vinnie*

**Statistics**

A random sample of 50 students chosen from an elementary school with 400 students was found to have a mean allowance of $26 per week with a standard deviation of $8. Obtain a 98% confidence interval for the total amount of allowance money given to students in this school per ...

*November 13, 2013 by Cam*

**Statistics**

The distribution of a sample of the outside diameters of PVC gas pipes approximates a symmetrical, bell-shaped distribution. The arithmetic mean is 11.0 inches, and the standard deviation is 2.0 inches. About 68 percent of the outside diameters lie between what two amounts? 8....

*March 27, 2014 by Shawn*

**Algebra 2**

A simple random sample of 50 adults was surveyed, and it was found that the mean amount of time that they spend surfing the Internet per day is 54.2 minutes, with a standard deviation of 14.0 minutes. What is the 99% confidence interval for the number of minutes that an adult ...

*December 9, 2014 by Jasmine*

**statistics**

A new national survey found that Americans drink an average of 6 glasses of water daily, instead of the recommended 8. Assuming that the number of glasses of water is approximately normally distributed with a standard deviation of 1.7 glasses, what proportion of Americans ...

*April 16, 2015 by MJ*

**computers**

Although label choices vary for different printers, your textbook recommends __________ for laser and ink jet printers. A. Avery standard, 5160, Address B. Avery standard, 6150, Label C. Avery standard, 6150, Address D. Avery standard, 5160, Label I've looked through the book ...

*June 27, 2012 by julia*

**stats**

A random sample of 40 men drank an average of 20 cups of coffee per week during examination final, with the population standard deviation equal to 6 cups. A lower limit of an approximate 95% confidence interval the population average cup of coffee is (1) 20.000 (2) 21.859 (3) ...

*March 31, 2010 by cindy*

**Math: i do not understand**

A tractor manufacturing company machines axles to extremely small tolerances. The main power axles have a mean diameter of 3.0000 inches and a standard deviation of 0.0050 inch. What is the probability that a given axle will have a diameter between 2.9915 and 3.0004 inches? ...

*May 7, 2010 by Bart*

**ap stats**

based on over 800 housing prices collected at random from the city of Los Angeles, an investigator constructed a histogram and found that the distribution of housing prices was heavily skewed to the right. Which of the following statistics will best represent the center of ...

*May 13, 2014 by emma*

**Statistics**

Cellular Phone Sales The probability that a cellular phone company kiosk sells X number of new phone contracts per day is shown below. Find the mean, variance, and standard deviation for this probability distribution. X 4 5 6 8 10 P (X) 0.4 0.3 0.1 0.15 0.05 What is the ...

*April 10, 2012 by Victor*

**math PLEASE URGENT**

if normal blood cholestrol level is 5.8 mM and a treatment caused a drop of 1.0 mM with a standard deviation of the difference of 2.0 mM what is the minimum number of individuals that should be used in the drug trial to determine whether or not it is effective i know you have ...

*June 1, 2010 by lou*

**Statistics**

Thomas economic forecasting, Inc. and Harmon econometrics have the same mean error in forecasting the stock market over the last ten years. However, the standard deviation for Thomas is 30 points and 60 points for harmon.At the .05 signifcance level can we conclude that there ...

*August 7, 2010 by Anonymous*

**statistics**

Given that x is a normally distributed random variable with a mean of 60 and a standard deviation of 10, find the P(56 < x <74). Please show all your work and write your answer in a complete sentence. Using the information from question 1, what percentage of the ...

*July 23, 2012 by Rachel*

**statistics**

Listed below are the duration's (in hours) of a simple random sample of all flights of a space shuttle program. Find the range, variance, and standard deviation for the sample data. Is the lowest duration time unusual? Why or why not? 71 100 237 199 164 269 193 379 252 233 388...

*February 11, 2015 by slomo*

**Finance**

Use the following information to calculate the covariance of asset A with an equally weighted portfolio of assets B and C. Asset Standard Deviation A 20% B 30% C 40% The correlation coefficient between A and B is 0.6. The correlation coefficient between A and C is 0.5. The ...

*September 22, 2014 by Anonymous*

**Math-Answer included**

{9, 7, 13, 24, 32, 45, 47} First you have to find the mean The mean is 9+7+13+24+32+45+47=177/7=25.2857=25.29 Find the standard deviation for the given data. Round your answer to one more decimal place than the original data. {9, 7, 13, 24, 32, 45, 47} (25.29-9)^2=16.29^2=265....

*November 6, 2009 by Anonymous*

**Math**

A consumer buys n light bulbs, each of which has a lifetime that has a mean of 800 hours, a standard deviation of 100 hours, and a normal distribution. A light bulb is replaced by another as soon as it burns out. Assuming independence of the lifetimes, find the smallest n so ...

*April 27, 2011 by Alex*

**Math**

A consumer buys n light bulbs, each of which has a lifetime that has a mean of 800 hours, a standard deviation of 100 hours, and a normal distribution. A light bulb is replaced by another as soon as it burns out. Assuming independence of the lifetimes, find the smallest n so ...

*April 27, 2011 by Lo*

**Statistics**

Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Label and ...

*May 13, 2011 by tom*

**statistics**

A state administered standardized reading exam is given to eighth grade students. The scores on this exam for all students statewide have a normal distribution with a mean of 506 and a standard deviation of 69. A local Junior High principal has decided to give an award to any ...

*September 4, 2014 by Anonymous*

**Business Statistics**

A filling machine is designed to fill soda bottles with 16 ounces of soda. The distribution for the weight of the bottles is normal. Twenty bottles are selected and weighed. The sample mean is 15.3 ounces and sample standard deviation is 1.5 ounces. Develop a 90% confidence ...

*March 16, 2015 by Leo Elvis*

**P-Chem**

The equilibrium constant K for the hydrolysis of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and phosphate is 1.66X10^5 at 37 degrees celcius, and Standard Delta H is -20.1 kJ/mol. Calculate Standard Delta S for the hydrolysis at 37 degrees celcius. On the ...

*October 20, 2006 by Angela*

**statistics**

If we know that the length of time it takes an MBA student to find a parking spot near the DePaul Center follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the point in the distribution that 75.8% of the MBA students exceed when...

*January 19, 2012 by mehul*

**math**

Assume that the average annual salary for a worker in the United States is $30,500 and that the annual salaries for Americans are normally distributed with a standard deviation equal to $6,250. Find the following: (A) What percentage of Americans earn below $19,000? (B) What ...

*October 25, 2012 by Jen*

**Math**

Assume that the average annual salary for a worker in the United States is $30,500 and that the annual salaries for Americans are normally distributed with a standard deviation equal to $6,250. Find the following: (A) What percentage of Americans earn below $19,000? (B) What ...

*October 28, 2012 by Michael*

**Statistics**

The Amount of filling a half-liter (500ml)soft drink bottle is normally distributed. The process has a standard deviation of 5ml. The mean is adjustable. A. Where should the mean be set to ensure a 95% probability that a half-liter bottle will not be under filled? B. A 99% ...

*April 11, 2014 by KT*

**Math/Probability/Statistics**

Find the expected value and the standard deviation in the following raffle: Value Tickets Grand Prize: $2,000.00 1 Second Place Prize: $800.00 20 Third Place Prize: $40.00 60 Fourth Place Prize: $30.00 300 Total Number of Tickets Sold: 10000

*October 22, 2015 by Anonymous*

**algebra 2b**

A simple random sample of 50 adults was surveyed, and it was found that the mean amount of time that they spend surfing the Internet per day is 54.2 minutes, with a standard deviation of 14.0 minutes. What is the 99% confidence interval (z-score = 2.58) for the number of ...

*May 17, 2016 by kevin*

**Statistics**

is the standard deviation a measure of the center or distribution... my teacher told me center i read the article and i\'ve been lead to believe its a measure of the distribution not the center... if it is a measure of the center how is it? I think it\'s a measure of the ...

*August 30, 2009 by Statistics*

**Stats**

National Packing Materials Company claims its X20 box can hold loads up to at least 80 pounds. Smith Widget Company has been using the boxes for one year and feels the boxes fail at lighter loads. Hearing the complaints from Smith, the lead engineer for National Packaging ...

*September 14, 2008 by Arthur*

**Statistics**

A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers. The suppliers' prices are the same. However, Supplier A's tires have an average life of 60,000 miles with a standard deviation of 10,000 miles. Supplier B's tires ...

*December 17, 2009 by Tykrane*

**Statistics**

A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers. The suppliers' prices are the same. However, Supplier A's tires have an average life of 60,000 miles with a standard deviation of 10,000 miles. Supplier B's tires ...

*December 17, 2009 by Tykrane*

**Statistics**

1. A simple random sample of FICO credit rating scores is listed below: 714 751 664 789 818 779 698 836 753 834 693 802 a. Find range, variance, and standard deviation. b. As of this writing, the mean FICO score was reported to be 678. Based on these results, is a FICO score ...

*October 5, 2013 by Shannon*

**algebra**

Three firms carry inventories that differ in size. Firm A's inventory contains 2000 items, firm B's inventory contains 5000 items, and firm C's inventory contains 10,000 items. The population standard deviation for the cost of the items in each firm's inventory is = 144. A ...

*December 30, 2014 by Anksuh*

**statistics**

drug company promises to help people lose at least 3 pounds per week. 15 people use the drug. they lose an average of 2.8 lbs per week with a standard deviation of .5lbs. is this a left tail or right tail and why?

*June 11, 2012 by Anonymous*

**Statistics**

Please can some one help me with the following: A fisherman finds that approximately 17% of all his fish go bad by the time he takes them to the market. The fisherman catches 1,000 fish. A. How many will go bad by the time he takes them to the market? B. Find the standard ...

*December 25, 2012 by Alia*

**Statistics**

Please can some one help me with the following: A fisherman finds that approximately 17% of all his fish go bad by the time he takes them to the market. The fisherman catches 1,000 fish. A. How many will go bad by the time he takes them to the market? B. Find the standard ...

*December 26, 2012 by Alia*

**Statistics**

32% of adult internet users have purchased products or services online. For a random sampling of 200 adult users, find the mean, variance and standard deviation for the number who have purchased goods or services online?

*March 17, 2013 by Kay*

**statistics**

a random sample of 80 college students was selected to participate in a experiment. the mean of the sample is 317 points, the standard deviation of 37 there are 310 students that didn't complete the experiment 1. compute the appropriate test statistic? 2. what is the critical ...

*July 11, 2012 by Anonymous*

**statistics**

SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of about 100 points, and are approximately normally distributed. What SAT I score within the population would have a percentile rank of approximately 97.5? Show all work as to how ...

*September 29, 2012 by Anonymous*

**Statistics**

Scores on a visual perception test are normally distributed with a mean of 2020 and a standard deviation of 250. a)If one subject is randomly selected and tested, find the probability of a score greater than 1800 b)if 50 subjects are randomly selected and tested fid the ...

*March 21, 2013 by Sunshine*

**statistics**

Scores on a visual perception test are normally distributed with a mean of 2020 and a standard deviation of 250. a)If one subject is randomly selected and tested, find the probability of a score greater than 1800 b)if 50 subjects are randomly selected and tested fid the ...

*March 21, 2013 by Sunshine*

**math**

A study conducted by a TV station showed the number of televisions per household and the corresponding probabilities for ecach. Find the mean, variance, and standard deviation. (in table) Number of televisions 1 2 3 4 Probability P(X) 0.32 0.51 0.12 0.05 If you were talking a ...

*April 10, 2013 by Lesley*

**Math**

The average monthly mortgage payment including principal and interest is $982 in the United States. If the standard deviation is approximately $180 and the mortgage payments are approximately normally distributed, find the probability that a randomly selected monthly payment ...

*April 10, 2013 by Lesley*

**statistics**

A scale measuring prejudice has been administered to a large sample of respondents. The distribution of scores is approximately normal with a mean of 31 and a standard deviation of 5. What percentage of sample had scores 1) Below 20 2) Above 40 3) Above 20 4) Below 40 5) Below...

*September 30, 2011 by Brady*

**Statistics**

When finding a confidence interval for a population mean based on a sample of size 11, which assumption is made? The standard deviation is fixed. The sampling distribution of z is normal. The sampling distribution of the sample means is approximately normal. There is no ...

*October 26, 2012 by What?*

**Statistics**

women's heights are normally distributed with a mean 63.1 in and standard deviation of 2.5. A social organization for tall people has a requirement that women must be at least 69in tall. What percentage of woman meet that requirement? The percentage of woman that are taller ...

*June 1, 2013 by Jenn*

**business statitics**

a) The mean lifetime of a sample of 100 light tubes produced by a company is found to be 1570 hours with standard deviation of 80 hours. Test the hypothesis that the mean lifetime of the tubes produced by the company is 1600 hrs. (7 marks)

*October 27, 2015 by john*

**statistics (7)**

The average cost per night of a hotel room in New York City is $273 (SmartMoney, March 2009). Assume this estimate is based on a sample of 45 hotels and that the sample standard deviation is $65. a. With 95% confidence, what is the margin of error (to 2 decimals)? b. What is ...

*April 23, 2014 by Vanessa*

**statistics (7)**

The average cost per night of a hotel room in New York City is $273 (SmartMoney, March 2009). Assume this estimate is based on a sample of 45 hotels and that the sample standard deviation is $65. a. With 95% confidence, what is the margin of error (to 2 decimals)? b. What is ...

*April 26, 2014 by Mia*

**Statistics**

Some IQ scores are standardized with a mean of 100 and a standard deviation of 16. Using the 68-95-99.7 Rule, Determine: 1. What percent of people would have an IQ score of no more than 68. (2).What percent of people would have an IQ score of 100 or above.

*February 25, 2008 by Math help*

**Algebra**

Mr. Smith has 100 students in his Algebra classes. The grades of a quiz are normally distributed with a mean of 70 and a standard deviation of 4. Sally claims that 75 students scored between 66 and 74 on this quiz. Given that this is normally distributed, is Sally correct?

*March 2, 2015 by Help is needed*

**Stats**

On Tuesday September 27, 2016 the high temperature increased to 36.7 degrees Celsius (98 degrees Fahrenheit). What is the probability that we observe a temperature of 36.7 degrees Celsius or higher given that the average temperature is 27 degrees Celsius with a standard ...

*October 8, 2016 by Kleena*

**Math**

In a random sample of 30 tires of the same type, it is found that the average life span is 36,200 miles with a standard deviation of 3800 miles. Find the interval about the sample mean such that the probability is 0.77 that the mean number lies within the interval. a. 35,402-...

*July 3, 2009 by Sophie*

**High School Math**

I'm reviewing for my final exam can anyone give me some tips on this I know what this means but I just to know someone eles opinion. Thanks Under what conditions might it be appropriate to use the mean? Median? Mode? When the median and mean are substantially different, what ...

*July 14, 2009 by Selena*

**statistics**

The time that it takes a randomly selected job applicant to perform a certain task has a distribution that can be approximated by a normal distribution with a mean value of 120 sec and a standard deviation of 25 sec. The fastest 10% are to be given advanced training. What task...

*April 8, 2011 by chels*

**Math 540**

The Department of Management Science at Tech has sampled 250 of its majors and compiled the following frequency distribution of grade point averages (on a 4.0 scale) for the previous semester. GPA Frequency 0-0.5 1 0.5-1.0 4 1.0-1.5 20 1.5-2.0 35 2.0-2.5 67 2.5-3.0 58 3.0-3.5 ...

*May 16, 2011 by Cassie*

**Stats**

The time that it takes a randomly selected job applicant to perform a certain task has a distribution that can be approximated by a normal distribution with a mean value of 150 sec and a standard deviation of 20 sec. The fastest 10% are to be given advanced training. What task...

*October 2, 2013 by B*

**statistics**

Reading placement scores for a particular college are normally distributed with a mean of 72 and a standard deviation of 7. a) draw a sketch of the reading placement scores for students at this college. be sure to mark the mean and also to mark one and two standard deviations ...

*June 3, 2012 by whitney*

**12th grade Math-statistics**

The annual sales, in millions, for 28 toy department stores is listed. A)Calculate the mean and standard deviation of the data. Answer to the nearest tenth. B) Calculate the percent of sales to the nearest whole number, that are: i)within one SD of the mean ii)within two SD of...

*December 12, 2008 by Jodine*

**Math**

The average daily high temperature for the month of September in Los Angeles is 27 degrees Celsius (81 degrees Fahrenheit) with a standard deviation of 2.78 degrees Celsius. How hot are the hottest 10.03% days during September in Los Angeles? Provide your answer to two decimal...

*October 8, 2016 by Kleena*