Sunday

December 21, 2014

December 21, 2014

Number of results: 8,348

**statistics**

The average price for new mobile homes is known to be distributed with a standard deviation of 350. if a random sample of 49 homes resulted in a sample mean of 38500, obtain a 90% confidence interval on the population mean.
*March 26, 2009 by April*

**statistics**

Assume that blood pressure readings are normally distributed with a mean of 123 and a standard deviation of 9.6. If 144 people are randomly selected, find the probability that their mean blood pressure will be less than 125
*November 8, 2011 by Anonymous*

**statistics**

Determine the probability that a sample of 49 boxes will have a mean weight below 365grams. past records show that the population mean is 368 grams and the population standard deviation is 7. the probability will be between
*November 30, 2011 by wanda*

**Statistics**

The weights of trout in a certain river follow a normal distribution with mean 3 pounds and standard deviation 0.8 pounds. What proportion of trout weigh between 3.2 pounds and 4.8 pounds? a.) .3891 b.) .9972 c.) .9452 d.) .5865
*December 1, 2011 by Jay*

**statistics**

what happens to the width of our confidence interval for mu if we increase the sample size but keep the confidence level the same ? a. it increases b. it stays the same c. it decreases d. it depends on the sample mean and standard deviation
*December 6, 2011 by jen*

**Statistics**

suppose a random sample of 360 students is drawn form a population of students. Among sampled, the average IQ score is 12 with standard deviation of 3. What is the upper confidence limit of the 95% confidence interval of the population
*March 14, 2012 by Arona Basuti*

**Statistics**

The distribution of heights of women aged 20 to 29 is approximately Normal with mean 63.6 inches and standard deviation 3 inches. The height (± 0.1 inch) of the middle 68% of young women falls between a low of inches and a high of inches.
*September 4, 2012 by Stacie*

**statistics**

supposed that the average weight loss for someone on a diet is 15 pounds with the standard deviation of 4 pounds. a sample of 18 adults enrolled a sswp have a mean weight loss of 15.83. using 0.01 level of significance.
*October 2, 2012 by jericho*

**statistics**

5. What happens to the width of our confidence interval for m if we increase the sample size but keep the confidence level the same? A) It increases. B) It decreases. C) It stays the same. D) It depends on the sample mean and standard deviation.
*May 8, 2013 by ali awan*

**statistics**

Assume that blood pressure readings are normally distributed with a mean of 123 and a standard deviation of 9.6. If 144 people are randomly selected, find the probability that their mean blood pressure will be less than 125.
*October 14, 2013 by florence *

**statisticss**

The time taken by a man to deliver milk is normally distributed with, mean 12 minutes and standard deviation 2 minutes. He delivers milk everyday estimate the probability that he takes. (a) longer than 17 minutes (b) between 9 and 13 minutes
*July 8, 2014 by Heidi*

**Probability**

Please help.. Find the probability of getting 2 hearts if the cards are drawn from a regular deck and the first card is not replaced. A true/false quiz consists of twenty questions. If a student answers the twenty questions by making random guesses, what is the probability of ...
*December 10, 2006 by Mary*

**math**

It is equally probable that stock A will have a +10% or -10% rate of return The only other possibility is that it will return 0%.The probability of 0% is twice that for a return of +10%. What is the expected return and Standard deviation of the return for stock A?
*September 24, 2014 by Anonymous*

**Chemistry**

When 0.312g of glucose was burned in a bomb calorimeter (heat capacity 641 J/K) the temperature rose by 7.739 K. Calculate the standard enthalpy of combustion and the standard internal energy of combustion. I've calculated the standard enthalpy but am unsure of how to go about...
*September 25, 2012 by Kalli *

**Statistics**

30 randomly selected cans of Coke are measured for the amount of cola in ounces. The sample values have a mean of 12.18 ounces and a standard deviation of 0.118 ounces. The 99% confidence interval is ( ounces, ounces). Round each result to two decimal places.
*November 9, 2013 by Katie*

**math**

The average selling price of homes in a certain city is $356,300. Assume the variable is normally distributed with a standard deviation of $64,600. If 396 homes are for sale, how many homes will sell for more than $325,000? (Round up to the next whole number.)
*November 28, 2011 by Jennifer*

**statistics**

A company produces batteries whose lifetimes are normally distributed with a mean of 100 hours. It is known that 90% of the batteries last at least 40 hours. (i). Estimate the standard deviation lifetime. (3 marks) (ii). What percentage of batteries will not last 70 hours?
*April 26, 2013 by Ravi*

**Math - Pre-Algebra**

44) A financial institution wishes to estimate the mean balances owed by its credit card customers. The population standard deviation is estimated to be $300. If a 98 percent confidence interval is used and an interval of ±$75 is desired, how many cardholders should be sampled...
*August 30, 2010 by BC*

**math**

at one high school the mean time for running the 100-yard dash is 15.2 seconds with a standard deviation of 0.9 seconds. The times are very close approximated by a normal curve. Find the percent of times that are: between 15.2 and 16.1 seconds
*July 14, 2008 by Leanne*

**statistics**

The amount of snow fall falling in a certian mountain range is normally distributed with a mean of 83 inches, and a standard deviation of 16 inches. What is the probability that the mean annual snowfall during 64 randomly picked years will exceed 85.8 inches?
*March 4, 2009 by kasey*

**math**

Find the z-score for the given raw score, mean, and standard deviation. Assume a normal probability distribution score = 15, ì = 16 , and ó = 2 Could you show me how to do this. My instructor has tried but I just don't understand how to do it and I have several questions to ...
*August 23, 2009 by sam*

**Statistics**

A lorry carries heavy cartons of goods. The weights of theses cartons are distributed about a mean of 100 kg and with a standard deviation of 7 kg. Find how many cartons the lorry can carry so that the probability of the total load exceeding 4500 kg is less than 0.5.
*April 18, 2012 by Sniper619*

**Q. Research**

3. Bob takes an online IQ test and finds that his IQ according to the test is 134. Assuming that the mean IQ is 100, the standard deviation is 15, and the distribution of IQ scores is normal, what proportion of the population would score higher than Bob? Lower than Bob?
*December 9, 2012 by Maurice*

**statistic**

A grain mill manufactures 100-pound bags of flour for sale in restaurant supply warehouses. Historically, the weights of bags of flour manufactured at the mill were normally distributed with a mean of 100 pounds and a standard deviation of 15 pounds. a. What is the probability...
*December 6, 2012 by anonymous*

**Statistics 2**

The body temperature of healthy human beings can be assumed to have a normal distribution with mean and standard deviation . Body temperature measurements taken from a sample of 130 healthy individuals shows the sample mean temperature to be 98.249O F and ...
*December 16, 2013 by Steven *

**Statistics**

In Professor White’s statistics course the correlation between the students’ total scores before the final examination and their final examination scores is r = 0.9. The pre-exam totals for all students in the course have mean 275 and standard deviation 50. The final exam ...
*October 21, 2012 by Kevin*

**graduate statistics**

Do children from lower socioeconomic status (SES) neighborhoods have lower than average test-taking skills? A researcher administered a standard measure of test-taking skills to a randomly chosen child from a low SES neighborhood and found him to have a score of 38. The ...
*July 3, 2013 by Anonymous*

**math**

The weights of adult long-tongued fruit bats are known to be normally distributed with a mean of 20.22 grams and a standard deviation of 3.23 grams. What is the probability that a randomly selected bat will: a) weigh at most 15 grams? b) weigh less than 30 grams?
*March 21, 2012 by becky*

**Math**

The weights of adult long-tongued fruit bats are known to be normally distributed with a mean of 20.22 grams and a standard deviation of 3.23 grams. What is the probability that a randomly selected bat will: a) weigh at most 15 grams? b) weigh less than 30 grams?
*March 23, 2012 by Becky*

**calculus**

The salaries at a corporation are normally distributed with an average salary of $29,000 and a standard deviation of $4,000. Sixteen percent of the employees make more than Sara. What is Sara's salary? Round your answer to the nearest dollar.
*June 5, 2012 by Sam*

**statistics**

Ramdom sample of 41 car owners results in a mean of 7 years. Population standard deviation of 3.75 years. Find a 95% confidence interval for the true population mean..My answer is (5.9, 8.1) but having problems with margin of error
*December 8, 2012 by Anonymous*

**statistics**

assume that the volume of drink is normally distributed, with a mean of 2.0 liters and a standard deviation of 0.05 liter. Using the random sample of 45 bottles. The probability is 99% that the sample mean will contain at least how much soft drink?
*March 19, 2013 by virginia*

**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? Please check work 70-65/8 = .625 = .2357 = 1.-.2357 = .7643 ANSWER 76% ????
*February 10, 2014 by Anonymous*

**statistics**

You have a score on a national entrance exam of 95. What percentage of people in the population have a score that is lower than yours? (Assume the population mean is 75 and the standard deviation is 10. Use the table I passed out in class.)
*February 26, 2014 by Anonymous*

**statics**

The standard deviation of the lifetime of certain TV picture tubes is estimated as 150 hours. How much large a sample must be taken in order to be 99% confident that the error in the estimated means lifetime will not exceed 25 hours
*November 18, 2014 by aima*

**Please help me with statistics**

I was asked to: Calculate the d value or effect size for A but use this data instead. A. Group one 12 and group two 11 standard deviation 3 Can anyone please help me figure out how to find the d value. Any help would be great.
*November 20, 2014 by Jennifer*

**math 3**

a sample of restraunts in a city showed that the average cost of a glass of iced tea is $1.25 with a standard deviation of 7 cents. if a new restraunt charges a price for iced tea that has a z value of 1.25, then what is the teas actual cost
*November 20, 2014 by raven*

**famu**

Construct a 99% confidence interval for the population mean, ì. Assume the population has a normal distribution. A group of 19 randomly selected employees has a mean age of 22.4 years with a standard deviation of 3.8 years. Round to the nearest tenth.
*December 1, 2014 by Anonymous*

**statistics**

2. The new Twinkle bulb has a standard deviation hours. A random sample of 77 light bulbs is selected from inventory. The sample mean was found to be 492 hours. a. Find the margin of error E for a 90% confidence interval. Round your answer to the nearest hundredths.
*May 2, 2010 by stefanie*

**college**

Essentials of statistics is the subject and the question is: The population of IQ scores forms a normal distribution with a mean of u=100 and a standard deviation of sigma=15. What is the probability of obtaining a sample mean greater than M=105 for a random sample of n=36 ...
*July 31, 2010 by Jennifer*

**Math**

i have a question regarding statistics. i just don't know how to do it and would really appreciate if someone could tell how i can solve it. the question is; a) compute the mean and the standard deviation of the population? ive looked through all my notes and my textbook and i...
*November 21, 2010 by ash*

**statistics**

The diameter of small Nerf balls manufactured at a factory in China is expected to be approximately normally distributed with a mean of 5.2 inches and a standard deviation of .08 inch. Suppose a random sample of 20 balls is selected. Find the interval that contains 87% of the ...
*June 28, 2012 by Josh*

**statistics**

The scores on a test for a very large class is normally distributed with mean 64 points and standard deviation 6 points. The department decides to award A to the highest 5% scores. What is the minimum score to receive an A for the course? Round your answer (down) to nearest ...
*July 11, 2012 by Anonymous*

**statistics**

Random samples of size n are selected from a normal population whose standard deviation is know to be 2. Suppose you want 90% of the area under the sampling distribution of x bar to lie within + or - 1 unit of a population mean u. Find the minimum sample size n that satisfies ...
*November 23, 2012 by joe*

**Stat Help Please**

Yearly stock returns on India's Sensex Index are well described by a Normal model with a mean of 18.36% and a standard deviation of 14.65%. give the stock return cutoff for the middle 30% of all years. I used TI-83 Calc. for these. Can someone check them? Thank you! Q1=InvNorm...
*March 10, 2013 by Taylor*

**Statistics**

1.The average number of acts of physical violence in a random sample of 150 TV movies was 4.5 acts with a standard deviation of 0.75. At the 95% confidence interval level, what is your estimation of the mean range of all movies shown in the television? Explain the result in ...
*October 4, 2013 by Chris*

**statistics**

A large number of applicants for admission to graduate study in business are given an aptitude test with a resulting mean score of 460 with a standard deviation of 80. The top 2.5 percent of the applicants would have a score of at what? A. 606 B. 617 C. 600 D. 646
*April 11, 2014 by Jill*

**Math statistics**

How large a sample should be taken if the population mean is to be estimated with 95% confidence to within $69? The population has a standard deviation of $892. (Round you answer up to the nearest whole number.) You may need to use the appropriate table in Appendix B to answer...
*June 8, 2014 by hanjay*

**Statistics**

Let's pretend the Work variable is normally distributed, with a mean/median/mode value of 22 and a standard deviation of 17. Based on these numbers, we can say that approximately 68 percent of SOC 390 students work between ______ and ______ hours per week.
*September 8, 2014 by Chris*

**Math- Statistics**

A random sample of size 36 is to be selected from a population that has a mean μ = 50 and a standard deviation σ of 10. * a. This sample of 36 has a mean value of , which belongs to a sampling distribution. Find the shape of this sampling distribution. * b. Find the ...
*February 8, 2011 by Tammy*

**statistics**

The scores on the final exam in a course have approximately a bell-shaped distribution. The mean score was 72, the highest score was 99, and the lowest score was 41. Use the value of the range (58) to estimate the value of the standard deviation. (Round your answer to the ...
*September 21, 2011 by Chris*

**statistics**

11. A local health care company wants to estimate the mean weekly elder day care cost. A sample of 10 facilities shows a mean of $250 per week with a standard deviation of $25. What is the 90 percent confidence interval for the population mean?
*June 18, 2012 by tristen*

**Statics**

A power company takes a random sample of its delinquent account files. For 400 accounts, the average delinquent amount was $239.30 with a standard deviation of $14.52. With 99% probability, determine the maximum error of the estimate for the mean of all the delinquent accounts.
*December 1, 2012 by Heather*

**Statistics**

Bob takes an online IQ test adn finds that his IQ according to the test is 134. Assuming that the mean IQ is 100, the standard deviation is 15, and the distribution of IQ scores is normal, what proportion of the poulation would score higher than Bob? Lower than Bob?
*August 11, 2013 by Opal*

**Statistics**

A university has 1,000 computers available for students to use. Each computer has a 250-gigabyte hard drive. The university wants to estimate the space occupied on the hard drives. A random sample of 100 computers showed a mean of 115 gigabytes used with a standard deviation ...
*October 27, 2013 by Shelby*

**Statistics**

Assume that the sample is taken from a large population and the correction factor can be ignored. The average teacher's salary is $43152. Suppose that the distribution is normal with standard deviation equal to $7000. If we sample 100 teachers' salaries, what is the ...
*February 3, 2012 by Renita*

**statistics**

I cant figure this out!!! The income of trainees at a local mill are normally distributed with a mean of $1100 and a standard deviation of $150. If a sample of 100 trainees is selected, what is the probability that the sample mean will be less than $1075 month?
*September 13, 2008 by Denim*

**Statistics**

Two problems: 1. Find D sub 3 of the following data set: 60, 40, 26, 33, 23, 53, 36, 23, 28, 12, 30, 47 2. Find P sub 26 of the following 25 scores: 38.5, 41.5, 52, 52.5, 61, 63, 63.5, 68, 69, 69, 78.5, 79, 80, 83, 87, 88.5, 88.5, 91, 91.5, 92, 92.5, 94, 94, 97, 97 I have a ...
*June 24, 2009 by Amy*

**statistics**

the average of final exam is 64, the standard deviation is 7. If the teacher set a rule that 1/4 of students who receive the poor grades should stay after class. lower than what mark should the students stay in school? does anyone know how to solve this?
*January 3, 2010 by K.T*

**statistics**

Suppose you administered an anxiety test to a large sample of people and obtained normally distributed scores with a mean of 45 and standard deviation of 4 There are 200 students in a sample. How many of these students will have scores that fall under the score of 41?
*September 9, 2011 by Jean*

**Statistics**

Suppose you administered an anxiety test to a large sample of people and obtained normally distributed scores with a mean of 45 and standard deviation of 4. There are 200 students in a sample. How many of these students will have scores that fall under the score of 41?
*September 9, 2011 by Jean*

**Stats...is this correct??**

Scores on the Stanford-Binet Intelligence scale have a mean of 100 and a standard deviation of 16, and are presumed to be normally distributed. A person who scores 68 on this scale has what percentile rank within the population? z = (68-100)/16 z = -32/16 = -2 So would it be ...
*October 18, 2011 by Jen*

**statistics**

the mean annual income for adult women in one city is and the standard deviation of the incomes is The distribution of incomes is skewed to the right. For samples of size 30, which of the following statements best describes the sampling distribution of the mean?
*April 8, 2012 by Taisha*

**statistics**

Scores on the ACT college entrance exam are Normally distributed with a mean µ = 20 and standard deviation σ = 5. An SRS of 25 ACT scores is selected, construct a 95% Confidence Interval for the sample mean (X-Bar) and interpret your result.
*December 3, 2012 by Alyssa*

**Statistics and Probability**

Commuters were asked how many times a week they stop for coffee on their way to work. A survey found a mean of 3 times a week with a standard deviation of 0.55. Find the probability that the sum of 100 values is more than 290.
*December 3, 2012 by Alley*

**Math**

A random sample of 42 college graduates revealed that they worked an average of 5.5 years on the job before being promoted. The sample standard deviation was 1.1 years. Using the .99 degree of confidence, what is the confidence interval for the population mean?
*February 2, 2013 by Jim*

**statistics**

The GPAs of all students enrolled at a large university have an approximately normal distribution with a mean of 3.02 and a standard deviation of .29. Find the probability that the mean GPA of a random sample of 20 students selected from this university is 2.87 or lower
*April 16, 2013 by lol*

**Statistics**

height shoe size (if you wear men's shoes, add 2) 61 6.5 67 9 63 7 66 8 60 6 71 10 71 11 63 8 63 7 66 62 7 64 6.5 61 7 64 7.5 63 8 58 6.5 63 9 62 6 61 7 74 60 6.5 60 7.5 63 8 Mean 63.73913043 7.571428571 Standard Deviation 3.922167667 1.296974501 H sub 0: x̄ = 8 H sub a...
*June 8, 2013 by Armando*

**STAT**

Assume that women’s heights are normally distributed with a mean given by µ = 64.6 inches and standard deviation given by σ = 2.2 inches. What area under the normal curve corresponds to the probability that a woman’s height is between 63.7 inches and 64.7 inches?
*October 12, 2013 by Jacky*

**STAT**

The weights of the 100 students in an introductory statistics class are normally distributed, with a mean of 170 pounds and a standard deviation of 5 pounds. How many students would you expect to have weight between 162 pounds and 178 pounds?
*October 12, 2013 by Jacky*

**Statistics**

As part of studying the relationship between mental and physical health, you obtain the following heart rates: 73 72 67 74 78 84 79 71 76 76 79 81 75 80 78 76 78 In terms of differences in heart rates, interpret these data using the following: (a) the range, (b) the variance...
*October 12, 2014 by J.T*

**Staatistics**

2 Packets of crisps from a production line have a weight distribution that is normal with a mean of 50.0 grams and a standard deviation of 2.0 grams. Samples are taken of size 36. 1. What is the probability that a sample mean is less than 49.0 grams? (Give answer to four ...
*December 14, 2014 by Natacha*

**statistics finding the shaded region**

Find the area of the shaded region. The graph depicts the IQ score of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15. The shaded region numbers are 85-120
*December 11, 2014 by Kelli*

**college STATISTICS**

Sample of 80 people randomly asked in casino shows that average lost per person is $160 with a standard deviation ó = $40. Based on this data create a 99% confidence interval for population mean. Does loss of $180 for single person contradict expectation? Explain your answer.
*March 7, 2010 by HELP*

**Statistics**

A math professor notices that scores from a recent exam are normally distributed with a mean of 64 and a standard deviation of 5. Answer the following questions using integer values. The professor decides to grade on a curve. If he wants 0.15% of the students to get an A, what...
*February 14, 2012 by Dora*

**stats**

An investment broker reports that the yearly returns on common stocks are approximately normally distributed with a mean return of 12.4 percent and a standard deviation of 20.6 percent. On the other hand, the firm reports that the yearly returns on tax-free municipal bonds ...
*October 3, 2013 by Help*

**statistics**

An investment broker reports that the yearly returns on common stocks are approximately normally distributed with a mean return of 12.4 percent and a standard deviation of 20.6 percent. On the other hand, the firm reports that the yearly returns on tax-free municipal bonds are...
*May 13, 2014 by please help!*

**math**

For a class of 43 students, for a certain test, the mean grade is 67 and the standard deviation is 7. a) how many students should receive a C? b) how many students should receive a B? c) what score would be necessary to obtain an A?
*November 7, 2008 by chase*

**Statistics**

In a distribution of 400 response times with a mean of 7 minutes and a standard deviation of 2 minutes, the maximum number of response times greater than 13 minutes would be about: A. 40 B. 100 C. 75 D. 90
*December 8, 2009 by Adria*

**statistics**

The average age of a child in kindergarden is 5 years or 60 months. The standard deviation is 12 months. If a random child is selected, find the probability that the childs age is between 54 and 66 months.
*October 31, 2011 by Anonymous*

**statistics**

The average score of all golfers for a particular course has a mean of 73 and a standard deviation of 3. Suppose 36 golfers played the course today. Find the probability that the average score of the 36 golfers exceeded 74.
*November 8, 2011 by Anonymous*

**Statistics**

Red has probability .30 and black has probability .70. What is the probability that patron will win all ten wagers if alternating between red and black on each wager? What would be the standard deviation?
*February 21, 2012 by Joe Dee.*

**math**

The lifetime of a SuperTough AAA battery is normally distributed with mean of 28.5 hours and standard deviation of 5.3 hours. For a battery selected at random, what is the probability that the lifetime will be 34 hours or less?
*November 26, 2012 by Sav*

**statistics**

The average admission charge for a movie is $6. if the distribution of movie admission charges is approximately normal with a standard deviation of $1, what is the probability that a randomly selected admission charge is less than $3.5?
*March 5, 2013 by Shenelle*

**statistics**

Norma finds her mean number of minutes per call to be 27, with a standard deviation of 6 minutes. The minutes per call are approximately normally distributed around 27 with no outliers.
*October 8, 2014 by Maragret*

**stat/ probability**

The height of males is normally distributed with a mean of 69 inches and a standard deviation of 2.5 inches. What is the probability that the height of a randomly selected male is between 66 and 71 inches?
*August 15, 2012 by mark*

**algebra 2**

"for 2000 patients, blood-clotting time was normally distributed with a mean of 8 seconds and a standard deviation of 3 seconds. What percent had blood-clotting times between 5 and 11 seconds
*May 21, 2008 by James*

**Statistics**

A random sample of size 20 from a normal population will sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the p-value and comment
*December 31, 2009 by Mrs. Lakshmi*

**statistics**

A random sample of size 20 from a normal population will sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the p-value and comment
*June 3, 2010 by masood*

**math**

In an intelligence test administered to 1000 childrens the average score is 42 and standard deviation 24.find (i)the number children exceeding the score 60. (ii) the number of the children with score lying between 20 and 40.
*March 2, 2011 by noopur*

**Statistics**

Suppose that the weight of male babies less than 2 months old is normally distributed with mean 11.5 pounds and standard deviation 2.7 pounds. What proportion of babies weigh less than 11.00 pounds?
*June 16, 2013 by Anonymous*

**statistics**

The height of an adult male is known to be normally distributed with a mean of 69 inches and a standard deviation of 2.5 inches. The height of the doorway is 74 inches. What proportion of adult males will not fit under the door?
*February 9, 2014 by judy*

**statistics**

A population has a mean of 300 and a standard deviation of 50. Suppose a sample of size 125 is selected and is used to estimate . What is the probability that the sample mean will be within +/- 3 of the population mean (to 4 decimals)?
*October 14, 2014 by Anonymous*

**statistics**

the marks of 100 students in an examination are normally distributed with mean of 25 marks and a standard deviation of 10 marks. Given that the pass mark is 20, estimate the number of students who passed the examination.
*October 24, 2014 by Mere*

**statistics**

For a certain group of individuals, the mean hemoglobin level in the blood is 21.0 grams per milliliter (g/ml). The standard deviation is 2 g/ml. If a sample of 25 individuals is selected, find the probability that the mean will be greater than 21.3 g/ml. Assume the variable ...
*October 22, 2010 by diandra*

**math**

the following table gives the amount of money john made selling ice cream treats during the local exhibition. determine the mean and standard deviation of john's income for these 11 days. round answer to nearest cent. day: 10 11 12 13 14 15 16 17 18 19 20 income: 65 56 75 45 ...
*January 18, 2011 by mike*

**math**

Suppose that an accounting firm does a study to determine the time needed to complete one person's tax forms. It randomly surveys 100 people. The sample average is 23.8 hours. There is a known population standard deviation of 6.0 hours. The population distribution is assumed ...
*November 19, 2011 by mayra*

**Math Calculator help**

Assume that a normal distribution has a mean of 21 and a standard deviation of 2. Use the empirical rule to find the percentage of values that lie above 23. Now I did this on the Ti 83 by using Normalcdf(-5,1) and getting an answer of 0.84 and then 1-0.84 and I get about 15.9 ...
*November 25, 2011 by HM*

**statistics**

any state auto insurance company took a random sample of 370 insurance claims paid out during a 1-year period. the average claim was $750 with a standard deviation of $150. find .99 confidence interval for the mean claim payment.
*April 27, 2012 by b*

**Statistics :(**

I have like 9 more of these problems, can someone please help me out so I can get started. thanx JS In a random sample of 35 tractors, the annual cost of maintenance was $4,425 and the standard deviation was $775. Construct a 90% confidence interval for this. Assume the annual...
*May 1, 2013 by Jessica*

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