Business Statistics - Exam 3 with Solution | BMGT 230, Exams of Business Statistics

Download Business Statistics - Exam 3 with Solution | BMGT 230 and more Exams Business Statistics in PDF only on Docsity! Business Statistics, BMGT230 Fall 2006 Studer-Ellis Examination 3 15 November 2006 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: Course& Section: BMGT 230 Fall 2006 Examination 3 COPY Z Print Name: Course & Section: 1z“Suppose a random sample of size 64 is drawn from a population with a mean value of 278. If the probability {hat a sample mean is Jess than 280 equals 0.8599, what is the standard deviation of the population? (SHOW work; 5 points) we OBERT neue EE, pears meet Pe (RS UP VEN Loe ail (220 - hh v cry VR ENG _ 2%. Holding all other values constant, does the width of a confidence interval increase, decrease, or remain the same (select one) when the sample size decreases? (3 points) UREA MEF 3z. Keith Entwistle, quality control manager at Quadrophenia Productions, constructed a confidence interval to estimate the mean time alt production workers take to complete a task. If the confidence interval ranged from 15.75 minutes to 19.50 minutes, what was the value of the associated sample statistic? (SHOW work; 3 points) 1.50 PH Bei. EIS se X ~~ eT Kev eRe = MOE MOE HO STS 4z. As the sample size, n, becomes large, the sampling distribution of means becomes approximately normal, regardless of the shape of the underlying population. The time it takes a popcorn kemel to pop in a certain microwave is distributed continuously and uniformly between 120 and 200 seconds. Determine the sample size (number of popcorn kernels) needed to estimate the true mean time (in seconds) for a kernel to pop with a margin of error of +/- 5 seconds at 99% confidence. (SHOW work; 10 points) LAD oy MOR = TH 5 weal" - \ V2. MO Ee beg Oy 11z. Confidence interval formulas have three parts: sample statistics, test statistics, and standard errors. In addition, the confidence interval formula for a single mean can generalize to two means (the parts are the same but they refer to differences between means). Suppose we select a random sample of 49 females and a random sample of 36 males. The 49 females have a mean height of 65 inches and the males have a mean height of 69 inches. We know the standard deviation of the heights of all females equals 3 inches and the standard deviation of the heights of all males equals 4 inches: SET UP (but do NOT calculate) the formula to construct a 95% confidence interval to estimate the difference between the mean height for females and the mean height for males for all members of the population. (5 points) nee nya Ble Ry 20S Bye WA Gh, ooh 8 oye 12z. To determine which of two seeds is better, a state agricultural station chose 7 two-acre plots of land randomly within the state. Each plot was split in half (meaning, into two equal parts), and a fair coin was tossed to determine which half would be sown with seed A and which half would be sown with seed B. The yields, in bushels, follow: Plot Seed A Seed B 1 82 88 2 68 66 3 109 121 4 95 106 5 112 116 6 16 79 7 81 89 a. Are the samples associated with the test independent or dependent? (3 points) Gap seth BAL b. State the null and alternative hypotheses associated with the test. (3 points) Hpe pan Se bef of Hot ys AO pA &. whos af oo. ahs c. If the level of significance equals 0.10, what is the critical value of the associated test statistic? (3 points) A=0.10 Kereta cone beats ® SER ete (tla 8 O08, bts we Me | IMG 2. d. If the calculated value of the associated test statistic equals —3.26311, state your decision. (3 points) beeete | > | bered => Rey eat tp 13z. The S. Brandt Corporation wants to compare five programs that train employees to perform a certain task. Twenty-five employees are randomly assigned to the training programs, with five employees in each program. At the end of the training period, a test is conducted to determine how many times the employees can perform the task in one mimute. The number of times the task is performed per minute is recorded for each employee, with the following results: Program 1 Program 2 Program 3 Program4 Program 5 15 14 24 8 17 16 16 20 18 12 Sum 90 70 Yak XG.F A 14 il 10 13 9 7 17 13 VL 20 15 13 16 2 2 80 60 50 Bays le Mg Fo Be State the null and alternative hypotheses associated with the test. (3 points) lp 8 ee ta ga tint ok Steen 2 mesans ARI ena a! ‘Complete the associated ANOVA table below (6 points): Source Sum of Squares Between 200 Within 200 Total Heo df. Mean Square Festc 4 50 5 1a 1 Ata = 0.05, what is the value of F,,,? (3 points) v Ferre Coe 0.90, liga 4, oe poy 2b] gp Siate your decision regarding the null hypothesis (3 points) Fei. * Ferre 2 KES EGT Hye af Tukey’s HSD (a = 0.05) equals 5.98, which specific training programs differ significantly from each other “with respect to how many times employees can perform the task per minute? (SHOW work; 3 points) 4 oe 8 4 \ og 4 on & 2 g@ -2 3% 3 oo YOR Brome es Be Iq R go Bua Cates ore on Pace a a o Boer sere BERGE ae sheearms *