3. An industrial psychologist wants to estimate the mean time necessary for workers in her company to learn a new computer operating system. Her company has a total of 597 employees. Previous studies have indicated that the standard deviation in the amount of time necessary to learn the new operating system in 80 minutes. To estimate the mean time necessary to learn the operating system to within 15 minutes with 95% confidence, a sample of how many workers would be necessary? а. 77 b. 93 с. 111 d. 122

3. An industrial psychologist wants to estimate the mean time necessary for workers in her company to learn a new computer operating system. Her company has a total of 597 employees. Previous studies have indicated that the standard deviation in the amount of time necessary to learn the new operating system in 80 minutes. To estimate the mean time necessary to learn the operating system to within 15 minutes with 95% confidence, a sample of how many workers would be necessary? а. 77 b. 93 с. 111 d. 122

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Description: 3. An industrial psychologist wants to estimate the mean time necessary for workersin her company to learn a new computer operating system. Her company has atotal of 597 employees. Previous studies have indicated that the standarddeviation in the am

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Suppose that the time in minutes it takes a student to complete an assignment is normally distributed with a mean 55 and variance 100 then the 35th percentile of the average time it takes a random sample of 49 students to complete the assignment is closest to О а. 51. O b. 59. О с. 49. O d. 54. О е. 56.
Suppose that the time in minutes it takes a student to complete an assignment is normally distributed with a mean 50 and variance 100 then the 35th percentile of the average time it takes a random sample of 49 students to complete the assignment is closest to a. 49. b. 46. OC. 51. O d. 44. Ое. 54.
Cranberry syrup is packaged using two production lines. A sample of 5 packs from the first line has a mean of 1.2 quarts with a standard deviation of O.02 quarts. A sample of 6 packs from the second line has a mean of 1.15 quarts with a standard deviation of 0.01 quarts. What is the value of the test statistic? * О 4 0.05 O 2 0.01
Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.
Dogsled drivers, known as mushers, use several different breeds of dogs to pull their sleds. One proponent of Siberian Huskies believes that sleds pulled by Siberian Huskies are faster than sleds pulled by other breeds. He times 4040 teams of Siberian Huskies on a particular short course, and they have a mean time of 7.77.7 minutes. The mean time on the same course for 4747 teams of other breeds of sled dogs is 6.26.2 minutes. Assume that the times on this course have a population standard deviation of 1.51.5 minutes for teams of Siberian Huskies and 1.61.6 minutes for teams of other breeds of sled dogs. Let Population 1 be sleds pulled by Siberian Huskies and let Population 2 be sleds pulled by other breeds. Step 1 of 2 : Construct a 95%95% confidence interval for the true difference between the mean times on this course for teams of Siberian Huskies and teams of other breeds of sled dogs. Round the endpoints of the interval to one decimal place, if necessary.
13)Many graduate schools require applicants to take the GRE for admission. The mean GRE score worldwide is 149.7 with a standard deviation of 8.2. The recommended overall GRE score for admission at UC Berkeley is 153 Q) If an applicant were to obtain a score of 123, how many standard deviations away is this score from the mean?
A man who moves to a new city sees that there are two routes he could take to work. A neighbor who has lived there a long time tells him Route A will average 5 minutes faster than Route B. The man decides to experiment. Each day he flips a coin to determine which way to go, driving each route 20 days. He finds that Route A takes an average of 45 minutes, with standard deviation 3 minutes, and Route B takes an average of 49 minutes, with standard deviation 5 minutes. Histograms of travel times for the routes are roughly symmetric and show no outliers. Complete parts a and b. (...) a) Find a 95% confidence interval for the difference between the Route B and Route A commuting times, (µÂ ¯ µÃ) - The confidence interval is (.). (Round to two decimal places as needed.)
2. Two stores at SM Downtown are selling batteries for cell phones. Store A claims an average battery life of 12 hours while Store B advertises an average of 14 hours. Why would we need to know the standard deviation of the battery life before deciding what brand to buy? Suppose the standard deviation are 1.5 hours for A and 1 hour for B, which battery is more likely to last all day?
9. [20 pts] A drug company has developed a new drug that is designed to reduce high blood pressure. To test the drug, a sample of 15 patients is recruited to take the drug. Their SBP are reduced by an average of 28.3 millimeters, with a standard deviation of 12.0 millimeters. In addition, another sample of 20 patients takes a standard drug. The blood pressure in this group are reduced by an average of 17.1 millimeters with a standard deviation of 9.0 millimeters. Assume that blood pressure reductions are approximately normally distributed with equal variances. Test the new drug is better than the standard drug. Use the a = 0.05. (a) Họ: (b) Hạ: (c) Test Statistic:
A quantity measured 50 times results in a mean x=23.345 +/- 0.0022 What is the standard deviation? What number of measurements will cut the standard deviation of the mean half? If a 100 measurement are taken, what is the new standard deviation?
6. A comparison of life expectancy in random samples of 40 less-developed countries and 31 industrialized countries reveals the following (fictional) data. The standard deviations are significantly different from one another. Is there a significant difference in mean life expectancy between countries with these two levels of economic development? X=life expectancy of the resident at birth. Less-Developed Countries Mean=66.1 years N=40 Standard error of the difference between means=.60 Industrialized Countries Mean=76.7 years N=31
3. A local hospital doctor's team reports that the average cost of treatment of heart disease is 800 RO. To see if the average cost of treatment is different at a particular hospital, a researcher selected a random sample of 40 patients and found that the average cost of treatment is 400 RO. The standard deviation of the population is 350 RO. At test the claim of the hospital doctors.