Friday

October 21, 2016
Number of results: 24,770

**statistics**

The mean scale score on the mathematics examinatin of ninth graders in Texas was 86 with a standard deviation of 5 points. Given a student was selected at random what is the probability tht his score was 91 or higher

*February 10, 2013 by kelly*

**statistics**

The mean scale score on the mathematics examinatin of ninth graders in Texas was 86 with a standard deviation of 5 points. Given a student was selected at random what is the probability tht his score was 91 or higher

*February 10, 2013 by kelly*

**Statistics **

Suppose. Population of test-scores is normally distributed with mean 65 and standard deviation 13 x~n (65,13) if you select a test at randome what is the probability that the score is below 60 or that it is between 65 and 70 please show work!

*March 10, 2013 by Alexa*

**statistics**

Assume that adults have IQ score that are normally distributed with a mean of 105 and a standard deviation 20. Find P, which is the IQ score separating the bottom 10% from the top 90%. Round to the nearest hundredth as needed.

*November 7, 2013 by angela*

**statistics**

Suppose the average body temp is 98.6 assume the variable is normally distributed with a standard deviation of .74 degrees. suppose a sample of 100 is taken. what is the probability that the mean is below 98.4??? Between 98.5 AND 98.7??

*March 21, 2014 by roger*

**statistics**

Assume that a standardized test is designed to have the mean score of 100 and the standard deviation of 15. At the 95% confidence interval, how large does the sample size have to be if the margin of error is to be 3 points?

*June 12, 2014 by virginia*

**Statistics**

Assume that a standardized test is designed to have the mean score of 100 and the standard deviation of 15. At the 95% confidence interval, how large does the sample size have to be if the margin of error is to be 3 points?

*June 15, 2014 by Anonymous*

**statistics**

In a time-use study, 20 randomly selected managers were found to spend a mean of 2.40 hours each day on paperwork. The standard deviation of the the 20 scores is 1.30. Also, the sample data appear to have a bell-shaped distribution. Construct the 95% confidence interval for ...

*July 30, 2012 by vickie*

**statistics**

In a time-use study, 20 randomly selected managers were found to spend a mean of 2.40 hours each day on paperwork. The standard deviation of the the 20 scores is 1.30. Also, the sample data appear to have a bell-shaped distribution. Construct the 95% confidence interval for ...

*July 30, 2012 by jamie*

**Algebra**

Over 350 students took a college calculus final exam. the scores of the students follow a normal distribution. using the information given below, determine the mean and the standard deviation for the students'scores. Give your answers to the nearest tenth of a percent. 1. 32% ...

*December 27, 2015 by Stephanie *

**statistics**

The length of country and western songs is normally distributed and has a mean of 200 seconds and a standard deviation of 30 seconds. Find the probability that a random selection of 9 songs will have mean length of 186.30 seconds or less. Assume the distribution of the lengths...

*July 29, 2013 by Anonymous*

**Statistics**

A study is being planned to estimate the mean number of semester hours taken by students at a college. The population standard deviation is assumed to be o=4.7 hours. How many students should be included in the sample to be 99% confident that the sample mean is within one ...

*March 25, 2012 by Jasmine*

**statistics**

the average score on the statistics quiz was a 70, and there was a standard deviation of 10 points. If the z-socre was -1.0 what is the percentile rank?

*March 2, 2014 by kim*

**statistics**

A bank’s loan officer rates applicants for credit. The ratings are normally distributed with a mean of 175 and a standard deviation of 15. If an applicant is randomly selected, find the probability of a rating that is between 150 and 200.

*June 22, 2011 by Jessica*

**statistics**

Scores for men on the verbal portion of the SAT-1 test are normally distributed with a mean of 509 and a standard deviation of 112. If a man is randomly selected, find the probablity tht his score is at least 571

*July 24, 2014 by jo ann*

**statistics**

If the score on a test has a mean of 52 and a standard deviation of 5, what is the z-score for a score of 58

*January 30, 2012 by Anonymous*

**stats**

Our students were asked to rate their admiration of Hillary Rodham Clinton on a scale of 1 to 7. They were asked to rate their Jennifer Lopez and Venus Williams on a scale of 1 to 7. The mean rating of Clinton was 4.06 with a standard deviation of 1.70. The mean rating of ...

*March 12, 2009 by sue*

**stats**

Our students were asked to rate their admiration of Hillary Rodham Clinton on a scale of 1 to 7. They were asked to rate their Jennifer Lopez and Venus Williams on a scale of 1 to 7. The mean rating of Clinton was 4.06 with a standard deviation of 1.70. The mean rating of ...

*March 12, 2009 by sue*

**statistics**

Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches. Find the probability that one randomly selected fence is under 54 inches.

*July 5, 2011 by K*

**statistics**

The heights of South African men are normally distributed with a mean of 64 inches and a standard deviation of 2 inches. a) What is the probability that a randomly selected woman is taller than 66 inches?

*December 8, 2011 by cassie*

**statistics**

The volumes of soda in quart soda bottles are normally distributed with a mean of 32.3 oz and a standard deviation of 1.2 oz. What is the probability that the volume of soda in a randomly selected bottle will be less than 32 oz?

*March 31, 2014 by olivo*

**Statistics**

Suppose the mean income of 35-year-olds in the US is $25,000. A random sample of 150 35-year-olds in California results in a sample mean income of $26,600 and a sample standard deviation of $3800. At the 5% significance level, ca we conclude that the true mean income of 35-...

*May 23, 2014 by jason*

**Stats**

Dee's store monthly sales for April, May, June are three independent random variables with means and variances as follow: April: Mean: $9500 Variance: $1250 May: Mean: $7400 Variance: $1425 June: Mean: $8600 Variance: $1610 a) find the mean and standard deviation of the total ...

*November 3, 2006 by Dee*

**statistics definition**

i have to find definitions and describe 208 words in my statistics class and for one of them it says: describe the deviation from a pattern of a graph. i don't actually get what it's asking me. i don't think it's pattern becuase i already have the definition for that. when it ...

*January 26, 2007 by david*

**Math3( Please Help Assignment Due)**

80 U2 songs (in seconds) were selected at random. Assume that the data is normally distributed and that the bands entire collection of songs has a mean and standard deviation equal to those calculated(mean=289.7 or 290, standard deviation= 76.8 or 77). What percentage of U2 ...

*June 27, 2016 by Jenny*

**math**

On a standardized test, Ann received a score of 85, which was exactly 2 standard deviations about the mean. If the standard deviation for the test is 4, what is the mean for this test?

*May 20, 2015 by debbie*

**Statistics (urgent)**

A beverage comopany uses a machine to automatically fill 1-liter bottles. Assume that the population of volumes is normally distributed. The company wants to estimate the mean volume of water to within 1 ML. Determine the minimum sample size required to construct a 95% ...

*November 18, 2012 by Erica*

**stats(help)**

Our students were asked to rate their admiration of Hillary Rodham Clinton on a scale of 1 to 7. They were asked to rate their Jennifer Lopez and Venus Williams on a scale of 1 to 7. The mean rating of Clinton was 4.06 with a standard deviation of 1.70. The mean rating of ...

*March 12, 2009 by Sue*

**math**

sample of 40 observations is selected from one population with a population standard deviation of 4.6. The sample mean is 101.0. A sample of 47 observations is selected from a second population with a population standard deviation of 4.0. The sample mean is 99.3. Conduct the ...

*February 2, 2015 by Phyllis*

**statistics**

the breaking strength of a cable known to be normally distributed with a mean of 4000kg and a standard deviation of 25kg.The manufacture prefers that at least 95% of its products meet a strength requirement of 4050 kg.Is this requirement being met? If not, by changing the ...

*September 5, 2011 by shruti*

**statistics**

the breaking strength of a cable known to be normally distributed with a mean of 4000kg and a standard deviation of 25kg.The manufacture prefers that at least 95% of its products meet a strength requirement of 4050 kg.Is this requirement being met? If not, by changing the ...

*September 5, 2011 by shruti*

**statistics**

the breaking strength of a cable known to be normally distributed with a mean of 4000kg and a standard deviation of 25kg.The manufacture prefers that at least 95% of its products meet a strength requirement of 4050 kg.Is this requirement being met? If not, by changing the ...

*September 5, 2011 by shruti*

**Statistics**

A quality control inspector wants to estimate the mean inside diameter of the washers produced by a certain machine. A preliminary sample indicates that the inside diameters have a standard deviation of 0.30 millimeters. What sample size does he need to estimate the mean to ...

*December 6, 2012 by Carolyn*

**Statistics**

A survey is being planned to determine the mean amount of time corporation executives watch television. A pilot survey indicated that the mean time per week is 12 hours, with a standard deviation of 3 hours. It is desired to estimate the mean viewing time within one quarter ...

*December 2, 2010 by Shyra*

**Statistics**

A private medical clinic wants to estimate the true mean annual income of its patients. The clinic needs to be within $500 of the true mean. The clinic estimates that the true population standard deviation is around $2,300. If the confidence level is 95%, find the required ...

*October 13, 2011 by Lorie*

**statistics defns**

What is the coefficient of variation and how do I calculate it from a dataset? coefficient of variation is simply the standard deviation divided by the mean.

*March 1, 2007 by weldon*

**statistics**

2. Children’s heights are normally distributed with a mean of 100 cm and a standard deviation of 6 cm. What proportion of children’s heights is smaller than 94?

*March 7, 2011 by Marie*

**statistics**

2.Children’s heights are normally distributed with a mean of 100 cm and a standard deviation of 6 cm. What proportion of children’s heights is smaller than 94?

*March 7, 2011 by Marie*

**Statistics**

Calculate the following: a) Determine the sample size necessary to estimate a population mean to within 1 with a 90% confidence given that the population standard deviation is 10. b) Suppose that the sample was calculated at 150. Estimate the population mean with 90% confidence.

*March 13, 2010 by Tom*

**statistics**

a random sample of 20 prices for summer sleeping bags was taken with a sample mean of $83.75 and a sample standard deviation of $29.97 a. Find a 95% confidence interval for the mean price of all summer sleeping bags. b. what is m i.e., what is the margin of error?

*April 29, 2012 by julie*

**Stats**

Exercise 6-8 The Downtown Parking Authority of Tampa, Florida, reported the following information for a sample of 235 customers on the number of hours cars are parked and the amount they are charged. Number of Hours Frequency Amount Charged 1 18 $3 2 33 7 3 49 10 4 44 15 5 34 ...

*September 28, 2010 by Nicole *

**Stats**

Cans of regular Coke are labeled as containing 12. Statistics students weighted the content of 10 randomly chosen cans, and found the mean weight to be 12.1. Assume that cans of Coke are filled so that the actual amounts are normally distributed with a mean of 12 and a ...

*October 20, 2012 by S*

**statistics**

GIVEN THE FOLLOWING STATISTICAL VARIABLES A:m(A)=5 B:m(B)=13 var(A)=25 Var(B)=6 1.calculate mean of Z= 4B-2A 2.Calculate the Standard Deviation assuming cov (A,B)=0

*August 17, 2010 by RASHMI*

**statistics**

a rocket club makes its own rockets. The rockets go to a mean height of 1100 feet with a standard deviation of 60 feet. if the club fires 36 rockets, what is probability that the mean heights of the rockets will be greater than 1080p feet

*July 13, 2014 by eric*

**statistics**

can you explain this to me please? Consider the binomial distribution where n = 11 and p = 0.05. Find the mean and standard deviation of this binomial distribution.

*November 5, 2014 by MissPatte*

**math**

A set of data items is normally distributed with a mean of 70. Convert the data item to a z-score, if the standard deviation is as given. data item: 80; standard deviation: 15

*April 17, 2016 by elizabeth*

**statistics**

the following data represents the percentages of family income allocated to groceries for a sample of 50 shoppers: percentage of family income #of shoppers 10-19 6 20-29 14 30-39 16 40-49 11 50-59 3 1.calculate the value of mean 1.1 meadian percentage of family income spent on...

*April 27, 2007 by mary*

**statistics**

The Frayed Nerves Anxiety Scale (FNAS) is used to measure the anxiety level of people on a scale from 0 to 1000. Four students were randomly chosen and given the FNAS before their second exam. Their scores were 700, 653, 740, and 707. The standard deviation sigma of the test ...

*October 17, 2011 by Anand*

**Statistics**

Find the margin of error for a 95% confidence interval for estimating the population mean when the sample standard deviation equals 100, with a sample size of (i) 400, (ii) 1600. What is the effect of the sample size? (b) Find the margin of error for estimating the population...

*April 4, 2015 by Courtney R*

**statistic**

Chebyshev's thereon- the author's generac produces voltage amounts with a mean of 125.0 volts and a standard deviation of 0.3 volt. using chebyshev's theorem,what do we know about the percentage of voltage amounts that are within 3 standard deviations of the mean? What are the...

*September 18, 2011 by marie*

**statistics**

A student scored 84 points on a test where the mean score was 79 and the standard deviation was 4. Find the student's z score, rounded to 2 decimal places

*February 24, 2012 by RGCLARK*

**statistics**

IQ scores are normally distributed with a mean u = 100 and a standard deviation o =15. Based on distribution, determine % of IQ scores between 100 and 120 =

*June 21, 2012 by Dianne*

**Statistics **

What is the appropriate sample size for a confidence interval around the sample mean if you want a margin of error of 0.8 with 95% confidence and a population standard deviation of 12.

*November 30, 2012 by Parul *

**statistics**

The test scores of students in a class test have a mean of 65 and with a standard deviation of 8. What is the probable percentage of students scored more than 70?

*February 10, 2014 by lisa*

**Statistics**

How do I answer: A normal distribution has a standard deviation equal to 39. What is the mean of this normal distribution if the probability of scoring above x = 209 is 0.0228

*September 1, 2016 by Brian*

**math**

A sample of 148 of our statistics students rated their level of admiration for Hillary Rodham Clinton on a scale of 1 to 7. The mean rating was 4.06, and the standard deviation was 1.70. (For this exercise, treat this sample as the entire population of interest.) a. Use these ...

*October 12, 2013 by eid2013*

**math **

A sample of 148 of our statistics students rated their level of admiration for Hillary Rodham Clinton on a scale of 1 to 7. The mean rating was 4.06, and the standard deviation was 1.70. (For this exercise, treat this sample as the entire population of interest.) a. Use these ...

*October 14, 2013 by eid2013*

**Statistics**

n=1000, bell-shaped Mean - 5,000 ~950 lie +/-100 of 5000 -4900 to 5100 Required 1) Standard Deviation 2) 97.5th percentile value 3) Z-score for 16th percentile

*September 26, 2010 by Rhea*

**statistics**

4. The scores on a university examination are normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 5% of students will fail the examination, what is the lowest score, to the nearest whole number, that a student can have and pass?

*February 3, 2011 by loni*

**Statistics**

The weights of adult males are normally distributed with a mean of 172 lb and a standard deviation of 29 lb. 1.Find the weight that divides the upper 2% of weights from the lower 98%. Can anyone please explain how to do this,I have no idea from where to begin. Thanks.

*March 8, 2011 by Plzz helpp*

**statistics**

the distribution of heights of American women aged 18 to 24 is approximately normally distributed with mean 65.5 inche and standard deviation 2.5 inches. what is the probability that a randomly seleted woman is between 60 and 64 inches tall?

*June 29, 2011 by Tee*

**Statistics Summary**

A bakery has an average daily expense of $1350. The standard deviation is $150. The owner takes a sample of 50 bills, what is the probability the mean of his sample will be between $1200 and $1500? how do i solve this

*January 17, 2012 by Yelena*

**statistics**

The weights of a group of adult males are normally distributed with a mean of 180lb and standard deviation of 8lb. Find the probability that a randomly chosen male from this group weighs more than 190lb.

*June 10, 2012 by tiffany*

**Statistics**

A shoe store knows that the purchase amount by its customers is a random variable that follows a normal distribution with a mean of $30 and a standard deviation of $9. What is the probability that a randomly selected customer will spend $30 or more at this store?

*December 27, 2012 by Anonymous*

**Statistics **

A random sample of 150 towns in a western state had a mean annual precipitation of 2.86 inches. Assume that the population standard deviation is known to be 0.78 inches. Compute the 95% confidence interval for μ.

*March 19, 2014 by Kathy *

**Statistics/Probability**

5) The product is sold in packets whose masses are normally distributes with mean of 1.42 kg and a standard deviation of 0.025 kg. (1) Find the probability that the mass of a packet, selected at random, lies between 1.37 kg and 1.45 kg

*July 17, 2014 by Koylar*

**Statistics**

Carrie attained a score of 650 on the verbal section of her SAT. The mean grade was a 500 with a standard deviation of 100. What percentage of test takers scored below and above Carrie?

*October 30, 2014 by Juan*

**statistics/normal distribution**

Find the area of the shaded region.The graph to the right depicts IQ scores of Adults (85-120), and those scores are normally distributed with a mean of 100 and a standard deviation of 15

*March 4, 2015 by slomomo*

**statistics**

If the mean value of the weight of a particular brand of dog food is 20.6 lb and the standard deviation is 1.3, assume a normal distribution and calculate the amount of product that falls below the lower specification value of 19.7 lb

*December 21, 2015 by sam*

**Statistics**

Suppose that a sample of 50 scores has a mean of Y=90 and the standard deviation is 15. Between what two values of Y will at least 90% of the scores fall? What is the maximun number of scores that can lie out of the interval?

*October 30, 2011 by Sara*

**Statistics**

The lifetimes of batteries produced by a firm are known to be normally distributed with a mean of 100 hours and a standard deviation of 10 hours. What is the probability a battery will last between 110 and 120 hours?

*November 24, 2011 by Brea*

**statistics**

The lifetime of a 2 volt non-rechargeable battery has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. What is the z- score for batteries with lifetimes of 520 hours

*September 3, 2012 by Gee*

**statistics**

The lifetime of a 2 volt non- rechargeable battery has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours.What is the z- score for batteries with lifetimes of 600 hours

*September 3, 2012 by Gee*

**statistics**

Waiting times at a doctor office are normally distributed with a mean of 35 minutes, and a standard deviation of 10 minutes. What is the chance a patient would have to wait over 50 minutes?

*November 5, 2014 by Cecy*

**statistics**

A coin mint has a specification that a particular coin has a mean weight of 2.5 g. A sample of 39 coins was collected. Those coins have a mean weight of 2.49491 g and a standard deviation of 0.01372 g. Use a 0.05 significance level to test the claim that this sample is from a ...

*March 7, 2015 by slomomo*

**statistics**

Do you want to own your own candy store? Wow! With some interest in running your own business and a decent credit rating, you can probably get a bank loan on startup costs for franchises such as Candy Express, The Fudge Company, Karmel Corn, and Rocky Mountain Chocolate ...

*December 2, 2012 by Anonymous*

**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*

**Statistics**

For a population with a standard deviation of 10, how mlarge a sample is necessary to have a standard error that is less than or equal to 5 points?

*March 2, 2011 by Denise*

**statistics**

Some test use a median of 50 and a standard deviation of 10. What proportion of the population will be between the standard score of 90 and 110?

*November 22, 2011 by Hm*

**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*

**Pyschological Statistics**

In a distribution with a standard deviation of eight, an individual score of 42 corresponds to a Z score of -0.5. What is the mean of this distribution?

*October 8, 2014 by Monique*

**Statistics**

A local grocery store wants to estimate the mean daily number of gallons of milk sold to customers. Assume the number of gallons sold follows the normal distribution, with a population standard deviation of 5.10 gallons. A random sample of 60 days shows that the mean daily ...

*October 27, 2013 by Joey*

**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*

**Statistic**

Twenty students assigned to an experimental group receive 30 in a control group has a mean of 38 on the test (with an estimated population standard deviation of 3); the control group has a mean of 35 (with an estimated population standard deviation of 5). Using the .05 level, ...

*October 10, 2009 by Anonymous*

**Statistics**

Find the margin of error for a 95% confidence interval for estimating the population mean when the sample standard deviation equals 100, with a sample size of (i) 400, (ii) 1600. What is the effect of the sample size? (b) Find the margin of error for estimating the population ...

*April 5, 2015 by courtney*

**Psychology**

Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a control group do not. After 6 months, both groups are tested on their knowledge. The experimental group has a mean of 38 on the test (with an estimated population standard ...

*September 19, 2011 by summer*

**college statistics**

a set of data is normally distributed with a mean of 1000 and a standard deviation of 100.what would be standard score for a score of 900.what percent of scores is betyween 1000 and 900.what would be percentile rank for a score of 900.

*June 3, 2012 by melba*

**statistics-normal distribution**

a set of data is normally distributed with a mean of 500 and a standard deviation of 100. a) what would the standard score fora score of 700 be? b) what % of scores is between 500 and 700? c) what would the percentile rank for a score of 700?

*October 28, 2010 by mary- can someone please solve,lost*

**statistics**

The MacBurger restaurant chain claims that the waiting time of customers for service is normally distributed, with a mean of 3 minutes and a standard deviation of 1 minute. The quality-assurance department found in a sample of 50 customers at the Warren Road MacBurger that the...

*June 23, 2008 by Renee*

**statistics**

The following information is available. H0: μ ≤ 10 H1: μ> 10 The sample mean is 12 for a sample of 36. The population standard deviation is 3. Use the .02 significance level.

*July 21, 2011 by Anonymous*

**statistics**

In a normal distribution with the mean being 500 and the standard deviation being 100, what raw score separates the top 40% of a distribution from the rest?

*July 29, 2012 by Jessica *

**statistics**

In a normal distribution with the mean being 500 and the standard deviation being 100, what raw score separates the top 40% of a distribution from the rest?

*July 29, 2012 by Jessica *

**statistics**

A normal distribution has a standard deviation equal to 23. What is the mean of this normal distribution if the probability of scoring above x = 181? record to 1 decimal place

*June 21, 2013 by Paisley*

**Statistics**

A random sample of 47 students studied for an average of 7.1 hours last week. If the population standard deviation is 1.2 hours, what is the 90% confidence interval for the population mean?

*April 18, 2014 by Monica*

**Statistics**

Assume that the unit of measure for each of the values in the sample is in dollars. What would be the units of measure for the sample: a) mean? b) range? C) Variance? d) Standard deviation?

*September 8, 2015 by Matt*

**statistics**

Let x be a continuous random variable that is normally distributed with a mean of 24 and a standard deviation of 7. Find the probability that x assumes a value between 27.5 and 59.0. Use Table IV in Appendix C to compute the probabilities. Round your answer to four decimal ...

*April 18, 2011 by Katie*

**statistics**

An automotive manufacturer has selected 10 car seats to study the Rockwell hardness of the seat recliner mechanism. A sample of 8 has an average of 44.795 and a standard deviation of 0.402. At 95% percent confidence level, what is the interval for the population mean?

*February 9, 2015 by t*

**statistics**

set of data is normally distributed with a mean of 200 and standard deviation of 50. · What would be the standard score for a score of 300? · What percentage of scores is between 200 and 300? · What would be the percentile rank for a score of 300? (Points : 6)

*August 26, 2011 by Laynette*

**Probability of Mean (Statistics)**

Assume 20 oz. cola bottles are filled so that the mean amount of liquid contained in the bottle is 20 oz and the standard deviation is .12 oz. If a case of 24 bottles is randomly selected from the population of all soda bottles, find the probability that the mean number of ...

*June 22, 2008 by thomas*