Monday

July 28, 2014

July 28, 2014

**Recent Homework Questions About Statistics**

Post a New Question | Current Questions

**statistics**

For a normal distribution, explain why we calculate the probability of a range of numbers instead of the probability of a single number on the lines below?
*Monday, June 9, 2014 at 6:51pm*

**statistics**

What is the null hypothesis for the following questions: Is there a relationship between heart rate and the number of cups of coffee drunk within the last 4 hours?
*Monday, June 9, 2014 at 6:33pm*

**statistics**

An investigator wants to estimate caffeine consumption in high school students. How many students would be required to estimate the proportion of students who consume coffee? Suppose we want the estimate to be within 5% of the true proportion with 95% confidence. Alpha = ...
*Sunday, June 8, 2014 at 7:26pm*

**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...
*Sunday, June 8, 2014 at 5:39pm*

**Math, statistics**

A trucking firm delivers appliances for a large retail operation. The packages (or crates) have a mean weight of 306 lb. and a variance of 2209. (Give your answers correct to four decimal places.) (a) If a truck can carry 4070 lb. and 25 appliances need to be picked up, what ...
*Sunday, June 8, 2014 at 9:08am*

**statistics**

company A has 110 employed, company B has 750 employed and company C has 250 employed. Compute the probability that an employee selected at random comes from company A or B.
*Saturday, June 7, 2014 at 2:48am*

**statistics**

The outcome of a standardized test is an integer between 151 and 200, inclusive. The percentiles of 400 test scores are calculated, and the scores are divided into corresponding percentile groups. Quantity A Minimum number of integers between 151 and 200, inclusive, that ...
*Saturday, June 7, 2014 at 2:09am*

**statistics**

300 test results are integers ranging from 15 to 75, inclusive. Dominick’s result is clearly in the 80th percentile of those results, not the 79th or the 81st. Quantity A Number of other test results in the same percentile as Dominick’s Quantity B Maximum number of ...
*Saturday, June 7, 2014 at 2:07am*

**statistics**

solve: our health organization is interested in estimating the average value of outstanding accounts receivable. After selecting a sample of 100 accounts, suppose that the mean was $120 and the standard deviation was $40. Use these data to construct a 98% confidence interval. ...
*Friday, June 6, 2014 at 10:37pm*

**Statistics **

The life of a blood pressure monitor has a normal distribution with an average of 40 years and a standard deviation of one year. What should the warranty be to replace a malfunctioning monitor with - if the company does not want to replace more than 1% of all the monitor. ...
*Friday, June 6, 2014 at 4:25pm*

**Statistics**

The registration numbers of vehicles in a certain country use digits 1-999. If a visitor has just entered the country. What is the probability that the first car he sees has at least 2 identical digits? Ans: 29/111
*Friday, June 6, 2014 at 9:28am*

**math**

A sample of 64 statistics students at a small college had a mean mathematics ACT score of 28 with standard deviation of 4. Estimate the mean mathematics ACT score for all statistics students at college. Give the 95% confidence interval.
*Thursday, June 5, 2014 at 8:27pm*

**statistics**

What are the differences between hypothesis testing regarding population means drawn from small and large samples
*Thursday, June 5, 2014 at 6:53pm*

**STATISTICS**

Suppose that you are in a class of 29 students and it is assumed that approximately 16% of the population is left-handed. (Give your answers correct to three decimal places.) (a) Compute the probability that exactly five students are left-handed. (b) Compute the probability ...
*Thursday, June 5, 2014 at 11:10am*

**statistics**

suppose you roll two number cubes and pick a letter of the alphabet at random. find the probability you will roll two odd numbers and pick one of the letters k, l, or m.
*Wednesday, June 4, 2014 at 10:55pm*

**statistics**

The diameter of an electric cable is normally distributed, with a mean of 0.6 inch and a standard deviation of 0.02 inch. What is the probability that the diameter will exceed 0.62 inch? (You may need to use the standard normal distribution table.
*Wednesday, June 4, 2014 at 4:20pm*

**statistics**

Draw a stem-and-leaf plot for the data set. (Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values.) 60 14 24 35 22 37 14 23 19 33 15 16 50
*Tuesday, June 3, 2014 at 5:29pm*

**statistics**

the breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 125 and a variance of 25. The material is considered defective if the breaking strength is less than 113 pounds. What is the probability that a single, randomly selected piece ...
*Tuesday, June 3, 2014 at 5:27pm*

**statistics**

the breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 125 and a variance of 25. The material is considered defective if the breaking strength is less than 113 pounds. What is the probability that a single, randomly selected piece ...
*Tuesday, June 3, 2014 at 5:27pm*

**statistics**

Between 50 and 80 people are hired on a ship. 75% speak English only and 25% speak German only. What is the mean number of people that speak English only? Can this even be calculated?
*Tuesday, June 3, 2014 at 11:28am*

**statistics**

In how many ways can 24 identical white ball and 19 black ball be arranged in rows so that no black balls are together.
*Tuesday, June 3, 2014 at 10:19am*

**statistics**

In a class of 100 ,84% of the students have taken politics &16% of student have taken history.how many students have taken both subject of all the students take at least one of these subjects?
*Tuesday, June 3, 2014 at 10:17am*

**statistics**

An 8th grade history teached studied the statistics for her mid-term exam. The average grade for the mid-term was 84 points, and the standard deviation was 8 points. The Z-score for a student who scores 90 on the exam is: 84-90/8= -0.75
*Tuesday, June 3, 2014 at 7:36am*

**statistics**

Give the probability in decimal form (correct to two decimal places). A calculator may be helpful. Last semester, a certain professor gave 35 As out of 259 grades. If one of the professor's students from last semester were selected randomly, what is the probability that ...
*Sunday, June 1, 2014 at 9:48pm*

**Statistics/I am confused**

The breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 115 and a variance of 25. The material is considered defective if the breaking strength is less than 105 pounds. What is the probability that a single, randomly selected piece ...
*Saturday, May 31, 2014 at 10:43pm*

**statistics**

A sample of n= 4 scores has SS equals 48 what is the estimated standard error for the sample mean
*Saturday, May 31, 2014 at 6:29pm*

**Statistics**

A class obtained the following scores on a test. Test Score TestScore Frequency 90 1 80 6 70 10 60 3 50 2 40 3 What I did was 90+6(80)+7(10)+3(60)+2(50)+3(40)=1040 than divided by 25 which should give me the means it give me a fraction, I got the median right 70,mode right 70...
*Saturday, May 31, 2014 at 6:08pm*

**Statistics/ is this how I do it.**

Find the range and the standard deviation (correct to two decimal places). 83,96,100,100,103 find the range and standard deviation Do I that 5 numbers add that divide by 5 for the range I am not sure how to do standard deviation. Thank you
*Saturday, May 31, 2014 at 4:28pm*

**Statistics 1**

If light bulbs are normally distributed with a mean of 2500 hrs. and a standard deviation of 500 hrs. what percentage of light bulbs have a life span less than 2500 hrs.?
*Friday, May 30, 2014 at 11:14pm*

**statistics**

Can someone please help me understand how confidence intervals fit within the broader context of inferential statistics
*Thursday, May 29, 2014 at 9:02pm*

**statistics**

A researcher is measuring air quality samples. The average air quality of his samples is 60 clean units. If a raw score of a clean in a specific hospital room is 75 and the corresponding z-score is 5, what is the standard deviation of the dataset?
*Thursday, May 29, 2014 at 3:10pm*

**statistics**

A researcher finds that the correlation between variable A and variable B is r = +.20. She also finds that the correlation between variable C and variable B is r = -.40. Which relationship is scientifically more useful and by how much?
*Thursday, May 29, 2014 at 1:35pm*

**statistics**

in a positive skewed distrubtion with a mean (average) of 100 and median of 90 is What?
*Thursday, May 29, 2014 at 10:50am*

**statistics**

The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.03 inch. What is the probability that the diameter will exceed 0.83 inch? (You may need to use the standard normal distribution table. Round your answer to three ...
*Thursday, May 29, 2014 at 12:07am*

**statistics**

An average of 1.4 private airplanes arrive per hour at an airport. Let x denote the number of private airplanes that will arrive at this airport during a given hour. Calculate the probability distribution of x. Find the probability that x = 4.
*Wednesday, May 28, 2014 at 4:44pm*

**statistics**

A company director took a sample of salaries of 13 employees in a big school during a certain time. she divided the wages into three groups according to the different jobs: teachers, assistants and coordinators as displayed in the table below. She wanted to find out whether or...
*Tuesday, May 27, 2014 at 11:04am*

**statistics**

Fill in the blank in the sample below if the variables are independent in the sample like product do not like product old 10 7 young 40
*Sunday, May 25, 2014 at 12:19am*

**statistics**

what is the relationship between hypothesis testing, statistical significance, and Type I and II errors
*Saturday, May 24, 2014 at 10:24pm*

**Statistics**

1. This probability distribution shown below relates to the number of times a person goes to a local coffee shop per day. What is the expected mean (average) number of times a person goes to a local coffee shop per day? 2. What is the area equal to under a normal curve ...
*Friday, May 23, 2014 at 11:29am*

**Statistics**

A hotel chain is interested in evaluating processes. Guests can reserve a room by using either a telephone system or an online system that is accessed through the hotel's web site. Independent random samples of 80 guests who reserved a room by phone and 60 guests who ...
*Friday, May 23, 2014 at 1:01am*

**Statistics**

A survey of 1,000 adult Americans included the following question: "If the military draft were reinstated, would you favor or oppose drafting women as well as men?" Forty-three percent responded that they would favor drafting women if the draft were reinstated. Using...
*Friday, May 23, 2014 at 12:46am*

**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-...
*Friday, May 23, 2014 at 12:29am*

**statistics**

A bottling commpany produces bottles that hold 10 ounces of liquid . Periodically, the company gets complaints that their bottles are not holding enough liquid. To test this claim, the bottling company randomly samples 25 bottles and finds the average amount of liquid held by ...
*Thursday, May 22, 2014 at 4:46pm*

**Statistics**

Determine whether the following statements are true or false: 1. P(A and B)=P(B|A)P(B). 2. When A and B are independent, P(A)=P(B). 3. When A and B are independent, P(A|B)=P(A). 4. When A includes B, P(A|B)=1. 5. When B is the complement of A, P(A or B)=1. 6. When B is the ...
*Thursday, May 22, 2014 at 2:51pm*

**Statistics**

Coaching companies claim that their courses can raise the SAT scores of high school students. But students who retake the SAT without paying for coaching also usually raise their scores. A random sample of students who took the SAT twice found 427 who were coached and 2733 who...
*Thursday, May 22, 2014 at 1:03pm*

**Statistics**

Who is the king of late night TV? An Internet survey estimates that, when given a choice between David Letterman and Jay Leno, 52% of the population prefers to watch Jay Leno. Suppose that you randomly select three late night TV watchers and ask them which of the two talk show...
*Thursday, May 22, 2014 at 11:26am*

**Statistics/Probability**

So I tried solving the first one and apparently failed miserably, attempted both twice and got it wrong each time and I have one submission attempt left, so any help is definitely appreciated! 1. Hotels R Us has kept the following recordes concerning the number of guests in a ...
*Wednesday, May 21, 2014 at 2:01pm*

**statistics**

predict the score in statistics for a student whose score in mathematics is 30
*Wednesday, May 21, 2014 at 10:33am*

**Statistics**

A confidence interval for a population mean has a margin of error of 3.1. a)Determine the length of the confidence interval. b)If the sample mean is 56.7, obtain the confidence interval.
*Wednesday, May 21, 2014 at 5:01am*

**Statistics/Probability**

So I tried solving the first one and apparently failed miserably, attempted both twice and got it wrong each time and I have one submission attempt left, so any help is definitely appreciated! 1. Hotels R Us has kept the following recordes concerning the number of guests in a ...
*Tuesday, May 20, 2014 at 9:35pm*

**statistics**

A company has 140 employees, of which 30 are supervisors. Eighty of the employees are married, and 20% of the married employees are supervisors. If a company employee is randomly selected, what is the probability that the employee is married and is a supervisor?
*Tuesday, May 20, 2014 at 10:45am*

**statistics **

A test consists of 12 multiple choice questions with 5 choices for each question. As an experiment, you GUESS on each and every answer without even reading the questions. Probability of getting less than 4 questions correct on this test is:
*Tuesday, May 20, 2014 at 1:36am*

**Statistics**

In a random sample of 50 undergraduate students at a college, it was found that 44 students regularly access social networking websites from their college library. What is the margin of error for the true proportion of all undergraduates who access social networking sites from...
*Monday, May 19, 2014 at 3:20pm*

**statistics**

An IQ is designed so that the mean is 100 and the standard deviation is 23 for the population of Normal adults, find the sample size necessary to estimate the mean IQ score of statistics students Such that it can be said with 90% confidence that the sample mean is within 5 IQ ...
*Monday, May 19, 2014 at 1:40pm*

**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...
*Monday, May 19, 2014 at 6:18am*

**statistics**

36 people surveyed at random and learned that 20 people are in favor of a new shopping mall. What is a good estimate that person chosen at random in her town would favor a new shopping mall.
*Sunday, May 18, 2014 at 2:44pm*

**statistics**

A survey of 100 commuters finds the average commuting to work is 25.5 minutes with the standard deviation of 11.5 minutes. construct a 98% confidence interval for the mean commuting time of commuters answer: 100%-98%=2%=0.02=0.01=1.28 E=1.28.11.5 divide by 10= 1.47 (25.5-1.47...
*Sunday, May 18, 2014 at 8:19am*

**statistics**

A pop-music record firm wants the distribution of lengths of cuts on its record to have an average of 129 seconds and a standard deviation of 10 seconds so that disc jockeys will have plenty of time for commercials within each 5-minute period. The population times for cuts is ...
*Saturday, May 17, 2014 at 7:08pm*

**Statistics**

You are responsible for planning the parking needed for a new 256-unit apartment complex, and you are told to base the needs on the statistic "average number of vehicles per household is 1.9." Which average (mean, median, mode) would be best if: You wanted to be ...
*Saturday, May 17, 2014 at 12:41am*

**Statistics**

Describe whether the following study would most likely be "observational" or experimental", and why it would be so. The nurses on the 5th floor record the medicines administered everyday and report results to the doctors.
*Saturday, May 17, 2014 at 12:39am*

**Statistics**

Find the range and the standard deviation (correct to two decimal places). 77, 89, 96, 96, 102
*Friday, May 16, 2014 at 2:39pm*

**Statistics**

Please answer yes or no to the following question for my statistics project: Are you in favor of welfare for those in need?
*Friday, May 16, 2014 at 9:04am*

**statistics**

The number of vacation days taken by employees of a company is normally distributed with a mean of 14 days and a standard deviation of 3 days. For the next employee, what is the probability that the number of days of vacation taken is less than 10 days? More than 21 days?
*Thursday, May 15, 2014 at 3:52am*

**Statistics**

Suppose you are given data from a survey showing the IQ of each person interviewed and the IQ of his or her mother. That is all the information you have. Your boss has asked you to put together a report
*Wednesday, May 14, 2014 at 10:48pm*

**Statistics**

A study found that 82% of elementary students buy lunch at school at least once a month. How large a sample would be necessary to estimate the true proportion within four percentage points with 95% confidence
*Wednesday, May 14, 2014 at 12:50pm*

**statistics**

A test designed to check for sickle-cell anemia has an 85% chance of detection in that, if a person has the disease, there is an 85% chance that the test will be positive. And, if the person does not have the disease, there is an 85% chance that the test will be negative. We ...
*Tuesday, May 13, 2014 at 9:59pm*

**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 ...
*Tuesday, May 13, 2014 at 9:49pm*

**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...
*Tuesday, May 13, 2014 at 9:45pm*

**statistics**

A laptop computer manufacturer found that by improving their battery design, they could increase the time that the laptop computer could be used on a single charge. To verify this improvement, they compared a sample of 10 laptops installed with the improved batteries to a ...
*Tuesday, May 13, 2014 at 9:35pm*

**statistics**

Five coins all balanced the same were tossed 150 times. Note that, while the coins are all balanced the same, they may or may not be fair coins. Since five coins were tossed, the possible number of heads for each toss could be zero through five. The following table gives the ...
*Tuesday, May 13, 2014 at 9:18pm*

**business math**

Statistics show that the sales force of a certain company successfully closed 352 sales out of 800 sales calls. What was their percent success rate?
*Monday, May 12, 2014 at 8:11pm*

**Health Information Management Statistics**

In September, the hospital has 23.652 admissions. Of these, 1,569 were readmissions. What is the hospital's readmission rate
*Monday, May 12, 2014 at 2:00pm*

**Statistics**

A brewery's filling machine is adjusted to fill bottles with a mean of 33.8 oz. of ale and a variance of 0.005. Periodically, a bottle is checked and the amount of ale noted. (b) Let's say you buy 93 bottles of this ale for a party. How many bottles would you expect to...
*Monday, May 12, 2014 at 9:58am*

**Statistics**

A researcher believes that the percentage of people who exercise in California is greater than the national exercise rate. The national rate is 20%. The researcher gathers a random sample of 120 individuals who live in California and finds that the number who exercise ...
*Sunday, May 11, 2014 at 1:09am*

**Statistics**

) In a rural area, the infected rate of certain disease is 0.20 (i.e., 20%). A sample of 20 people is taken from the area - selections are independent. Define X as the number of people in the sample who are infected by the disease. (1) This X is a binomial variable. What are ...
*Friday, May 9, 2014 at 1:53pm*

**Statistics**

(25 pts, 5 pts each) The ounces of coffee that a machine dispenses in 5-ounce cups have normally distributed. Suppose a sample of size 6 was taken from this machine, as shown as follows: 5.05 5.03 5.10 5.02 4.98 5.00 (for all calculations, keep at least six decimal places) (1...
*Friday, May 9, 2014 at 1:44pm*

**statistics**

A vending machine company wants to check three of its machines to determine if they are properly dispensing 12 ounces of coffee. Their data is given below. Reference: Ref 11-4 Compute the test value for the coffee machines. Answer 2.25 5.06 6.62 4.86
*Friday, May 9, 2014 at 10:10am*

**Economics & Statistics **

In the least squares equation, Ŷ = 10 + 20X the value of 20 indicates ____________. The Y-intercept increases by 20 units for each unit increase in X That Y increases by 20 units for each unit increase in X That X increases by 20 units for each unit increase in Y The ...
*Thursday, May 8, 2014 at 11:58pm*

**statistics**

8.Jean Siskel is an entertainment analyst for West Coast Securities. He is trying to develop a model to estimate gross earning generated by a new movie release. He has collected the following data on 20 movies: Gross Earnings, Production Costs, Promotion Costs, and if the ...
*Thursday, May 8, 2014 at 9:38pm*

**Statistics**

In the least squares equation, Ŷ = 10 + 20X the value of 20 indicates ____________. The Y-intercept increases by 20 units for each unit increase in X That Y increases by 20 units for each unit increase in X That X increases by 20 units for each unit increase in Y The ...
*Thursday, May 8, 2014 at 6:31pm*

**statistics**

8.Jean Siskel is an entertainment analyst for West Coast Securities. He is trying to develop a model to estimate gross earning generated by a new movie release. He has collected the following data on 20 movies: Gross Earnings, Production Costs, Promotion Costs, and if the ...
*Thursday, May 8, 2014 at 5:01pm*

**statistics**

Plymouth Rock Securities is interested in finding out if there is a relationship between the number of new clients brought into the firm by a broker and the sales performance of the broker. A random sample of 11 brokers' records are reviewed to determine the number of new ...
*Thursday, May 8, 2014 at 4:59pm*

**statistics **

in the spring of 2001, a university had 40,000 registered students. to estimate the percentage of all students expecting to graduate in 4 years, a simple random sample of 225 students was drawn, 144 of the sample planned to graduate in 4 years. (a) were the draws made with or ...
*Thursday, May 8, 2014 at 4:55pm*

**statistics **

3. The personnel director of a corporation will study the overtime work during the previous year for the 2,575 clerical workers. A sample of 100 of these workers will be chosen at random from the files. The average and the standard deviation of the overtime hours will be ...
*Thursday, May 8, 2014 at 3:24pm*

**statistics **

4. John Rengel is the Quality Assurance Supervisor for Vino Supremo Vinyards. He knows that 10 percent of each box of corks is undersized. (6 pts) a) If he were to randomly select 120 corks from the next box, then how many of these corks would John expect to be undersized? b) ...
*Thursday, May 8, 2014 at 3:22pm*

**Math**

I have no idea how to calculate z scores Weights of the vegetables in a field are normally distributed. From a sample Carl Cornfield determines the mean weight of a box of vegetables to be 180 oz. with a standard deviation of 8 oz. He wonders what percent of the vegetable ...
*Thursday, May 8, 2014 at 12:45pm*

**Statistics **

The Jefferson valley bank claims that the variation of their wait time is less when using a single line that feeds three tellers as opposed to having threes peerage lines. Test the claim that the standard deviation for wait time is less than 1.9 minutes with a single feed line...
*Wednesday, May 7, 2014 at 9:54pm*

**statistics**

A student claims the average amount of time spent studying for an exam is less than or equal to 120 minutes. A random sample of 101 students is drawn from a normal distribution. The sample mean is 140 with a sample standard deviation of 20. Test the claim with a .01 level of ...
*Wednesday, May 7, 2014 at 9:48pm*

**Statistics**

A survey of 250 lobster fisherman found that they catch an average of 32 pounds of lobster per day with a standard deviation of four pounds. If a random sample of 30 lobster fisherman is selected, what is the probability that their average catch is less than 31.5 pounds?
*Wednesday, May 7, 2014 at 6:47pm*

**Statistics**

Problem: you work for a manufacturer of tires (average life of your tires is 60.000 km with a standard deviation of 8.000 km). A supplier offers you new material that he says will increase by 10% the mileage of the tires you produce. A) What are the hypotheses for the test you...
*Wednesday, May 7, 2014 at 6:34pm*

**statistics**

A quality supervisor for a factory that makes cell phone cases examines a sample of 46 cases. She finds that 8 cases are the wrong size. Which is the best prediction of the number of cases that will be the wrong size in a shipment of 3,000? A.)410 B.)475 C.)506 D.)522
*Wednesday, May 7, 2014 at 11:31am*

**Statistics (46)**

The 2003 Statistical Abstract of the United States reported the percentage of people 18 years of age and older who smoke. Suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of .30. a. How large a ...
*Tuesday, May 6, 2014 at 11:54am*

**Statistics (45)**

In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. How large a sample should be taken if the desired margin of error is two minutes at a 95% level of confidence? How large a sample should ...
*Tuesday, May 6, 2014 at 11:54am*

**Statistics (44)**

The travel-to-work time for residents of the 15 largest cities in the United States is reported in the 2003 Information Please Almanac. Suppose that a preliminary simple random sample of residents of San Francisco is used to develop a planning value of 6.35 minutes for the ...
*Tuesday, May 6, 2014 at 11:53am*

**Statistics (43)**

Consumption of alcoholic beverages by young women of drinking age has been increasing in the United Kingdom, the United States, and Europe (The Wall Street Journal, February 15, 2006). Data (annual consumption in liters) consistent with the findings reported in The Wall Street...
*Tuesday, May 6, 2014 at 11:52am*

**Statistics (42)**

A simple random sample of 60 items resulted in a sample mean of 96. The population standard deviation is 16. a. Compute the 95% confidence interval for the population mean (to 1 decimal). ( , ) b. Assume that the same sample mean was obtained from a sample of 120 items. ...
*Tuesday, May 6, 2014 at 11:52am*

**Statistics (41)**

A market research firm conducts telephone surveys with a 42% historical response rate. What is the probability that in a new sample of 400 telephone numbers, at least 150 individuals will cooperate and respond to the questions? In other words, what is the probability that the ...
*Tuesday, May 6, 2014 at 11:50am*

**Statistics (39)**

Suppose a random sample of size 40 is selected from a population with = 9. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite (to 2 decimals). b. The ...
*Tuesday, May 6, 2014 at 11:49am*

**Statistics (38)**

Many drugs used to treat cancer are expensive. BusinessWeek reported on the cost per treatment of Herceptin, a drug used to treat breast cancer (BusinessWeek, January 30, 2006). Typical treatment costs (in dollars) for Herceptin are provided by a simple random sample of 10 ...
*Tuesday, May 6, 2014 at 11:48am*

**Statistics (37)**

According to the Sleep Foundation, the average night's sleep is 6.8 hours (Fortune, March 20, 2006). Assume the standard deviation is .7 hours and that the probability distribution is normal. a. What is the probability that a randomly selected person sleeps more than 8 ...
*Tuesday, May 6, 2014 at 11:47am*

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