Minitab Output for Exercise 734 40 tees were randomly sampled from the last hour's pro- duction. Their weights (in ounces) are listed in the follow- ing table. 6. 0142 49.2950. 0.18503 -47.09 8.906 .247 251 .254 .253 .253 .248 .253 .255 .256 .252 253 .252 .253 .256 .254 .256 252 .251 .253 .251 .253 .253 .248 .251 .253 .256 .254 .250 .254 .255 f. What conditions must be satisfied for the test results to 249 .250 .254 .251 .251 .255 .251 .253 .252 .253 be valid? 7.35 Facial structure of CEOs. Refer to the Psychological a. Write Ho and Ha in terms of the true mean weight of Science (Vol. 22, 2011) study on using a chief executive the golf tees, A. officer's facial structure to predict a firm's financial perfor- b. Access the data and find x and s. mance, Exercise 6.20 (p. 341). Recall that the facial width- c. Calculate the test statistic. to-height ratio (WHR) for each in a sample of 55 CEOs d. Find the p-value for the test. at publicly traded Fortune 500 firms was determined. The e. Locate the rejection region for the test using a = .01. sample resulted in * = 1.96 and s = .15. An analyst wants f. Do the data provide sufficient evidence to conclude that to predict the financial performance of a Fortune 500 firm the process is not operating satisfactorily? based on the value of the true mean facial WHR of CEOs. g, In the context of this problem, explain why it makes The analyst wants to use the value of u - 2.2. Do you sense to call a the producer's risk and S the consumer's recommend he use this value? Conduct a test of hypothesis risk. for u to help you answer the question. Specify all the ele- ments of the test: Ho. Ha, test statistic, p-value, a, and your Applying the Concepts-Intermediate conclusion. 7.38 Unethical corporate conduct. Refer to the Behavioral 7.36 Trading skills of institutional investors. The trading skills Research in Accounting (July 2015) study of unethical of institutional stock investors were quantified and ana- corporate conduct, Exercise 6.15 (p. 340). Recall that cach lyzed in The Journal of Finance (April 2011). The study in a sample of 86 accounting graduate students was asked focused on "round-trip" trades, i.e., trades in which the to perform an unethical task (e.g., to bribe a customer), same stock was both bought and sold in the same quarter. and each subject's intention to comply with the unethical Consider a random sample of 200 round-trip trades made request score was measured. [Scores ranged from - 1.5 (in- by institutional investors. Suppose the sample mean rate tention to resist the unethical request) to 2.5 (intention to of return is 2.95% and the sample standard deviation is comply with the unethical request)]. Summary statistics on 8.82%. If the true mean rate of return of round-trip trades the 86 scores follow: * = 2.42,s = 2.84. One researcher, of is positive, then the population of institutional investors is the opinion that subjects will tend to perform the unethi- considered to have performed successfully. cal task, believes the population mean intention score a. Specify the null and alternative hypotheses for deter- will exceed 2. Do the data support this belief? Test using mining whether the population of institutional inves a = .01. tors performed successfully. 7.39 Time required to complete a task. When a person is asked, b. Find the rejection region for the test using "How much time will you require to complete this task?" a = .05. cognitive theory posits that people (e.g., a business consul- c. Interpret the value of or in the words of the problem. tant) will typically underestimate the time required. Would d. A Minitab printout of the analysis is shown below. the opposite theory hold if the question was phrased in Locate the test statistic and p-value on the printout. terms of how much work could be completed in a given [Note: For large samples, z == z.] amount of time? This was the question of interest to re- e. Give the appropriate conclusion in the words of the searchers writing in Applied Cognitive Psychology (Vol. 25, problem. 2011). For one study conducted by the researchers, each in a sample of 40 University of Oslo students was asked how Text of " = 0 va > 0 many minutes it would take to read a 32-page report. In a second study, 42 students were asked how many pages of a If Mean 981 Lower Sound 200 2.950 6.820 0. 624 1.919 94.73 0.002 lengthy report they could read in 48 minutes. (The students in cither study did not actually read the report.) Numerical descriptive statistics (based on summary information pub- 7.37 Producer's and consumer's risk. In quality-control applica- lished in the article) for both studies are provided in the tions of hypothesis testing, the null and alternative hypoth- accompanying table. TEES eses are frequently specified as Ho: The production process is performing satisfactorily. Estimated Estimated Ha: The process is performing in an unsatisfactory manner. Time (minutes) Number of Pages Sample size, n Accordingly, a is sometimes referred to as the producer's 42 Sample mean, x 60 28 risk, while # is called the consumer's risk (Stevenson, Sample standard 41 14 Operations Management, 2014). An injection molder pro- deviation, s duces plastic golf tees. The process is designed to produce tees with a mean weight of .250 ounce. To investigate a. The researchers determined that the actual mean time whether the injection molder is operating satisfactorily, it takes to read the report is a = 48 minutes. Is thereA B C Weight Mean 0.252475 x- bar Standard Error 0.000352623 Median 0.253 Mode 0.253 Standard Deviation 0.002230183 s Sample Variance 4.97372E-06 s-squared Kurtosis 0.045806069 Skewness -0.476193713 Range 0.009 Minimum 0.247 Maximum 0.256 Sum 10.099 Count 40 n Confidence Level(90.0%) 0.000594126