Exam # 3 - Business Statistics | BMGT 230, Exams of Business Statistics

Download Exam # 3 - Business Statistics | BMGT 230 and more Exams Business Statistics in PDF only on Docsity! Business Statistics, BMGT230 Spring 2007 Studer-Ellis Examination 3 16 4pn12007 COPY Z Please provide the information requested below and on the next page SHOW all relevant work When necessary, carry values out to at least three (3) decimal places. Good Luck! ( Last Name (print): First Name (print): Honor Code Signature: ( )urse & Section: 165 BMGT 230 int Name: Spring 2007 Examination 3 Course & Section: COPY Z 12. Suppose the average checkout tab for all customers at a large supermarket equals $65.12 with a standard deviation of $21 .42.Thirty-three out of 100 times when a random sample of 49 customer tabs is selected, the sample mean should exceed what value (FORMULA, with NUMBERS, REQUIRED)? (10 points) ( z. Crystal Presley, an executive with Time-Wamer Music, has asked you to select a random sample of months \, and to construct a99o/o confidence interval estimate for the mean number of CDs the company sells each month. After you show the confidence interval estimate to Crystal, she comments that the interval "seems too narrow." If Crystal wants to keep the level of confiden ce at 99o/o and the values of the mean and standard deviation remain constant, what can you do to increase the width of the interval (FIVE or FEWER words, please!)? (5 points) if(rr.jr,:() -J 3z.To reduce waiting times for customers, an airline at BWI airport introduced the "snake system." Under this system, all customers enter a single waiting line that winds back and forth in front of the counter. A customer who reaches the front of the line proceeds to the next free position. The 95o/o confidence interval for the long- run (or population) waiting time equaled 14.40795 to 19.59205. If the average waiting time before the "snake system" was introduced equaled 21 minutes, use the confidence interval to determine which of the following statements is true (CIRCLE the corresponding roman numeral; 5 points): i. The "snake system" did not reduce the average waiting time. ii. The "snake system" did reduce the average waiting time, but the reduction was not statistically significant. . The "snake system" did reduce the average waiting time, and the reduction was statistically significant. " iv. One can not use a confidence interval to determine whether the "snake system" reduced the average waiting time significantly. I AI 166 ( l2z. An advertisement for Do-It-Now, Incorporated, a time management firm, guarantees that individuals who take the Corporation's super time management seminar will increase their productivity or the Corporation will .fund the seminar fee. Ineed Justice, a consumer rights activist, tested the claim in the advertisement. Ineed elected 21 individuals and counted the number of times they performed a simple task in 60 minutes before and after taking the super time management seminar. a. Are the samples independent or dependent? (3 points) b. State the null and alternative hlpotheses associated with the test Ineed conducted. (3 points) c. If cr:0.01, determine the critical value of the associated test statistic (include ALL relevant information and the sign or signs). (3 points) d. If the calculated value of the associated test statistic equaled -3.578, state the decision regarding the null hypothesis. (3 points) 169 ,,rr.rn"Sadie Ronald Corporation wants to compare four programs that train employees to perform a certain task. Thirty-two employees are randomly assigned to the training programs with eight employees in each ogrmn. At the end of the training period a test is conducted to determine how many times the employees can -rform the task in one minute. The number of times the task is performed per minute is recorded for each employee as follows: Proeram 1 t2 t4 10 9 12 15 11 13 Prosam 2 Proeram 3 Proeram 4 21124 22135 t9147 25 129 22178 23 11 10 20146 24 l1 7 936 MEAN SOUARE Fsa,s 78 a. State the null and alternative hypotheses associated with the test. (3 points) b. Complete the associate ANOVA table below (6 points): SUM OF SOUARES d.f.SOURCE / -:tween t Within Total c. If cr: 0.05, what is the critical value of the associated test statistic (include ALL relevant information)? (3 points) d. State your decision regarding the null hypothesis. (3 points) e. If Tukey's HSD (cr:0.05) equals 2.75, which specific training programs differ significantly from each other .'ith respect to how many times employees can perform the task per minute? (4 points) 170