The Stocks included in the S & P 500 are those of large publicly held companies that trade on either the New York Stock Exchange or the NASDAQ. In 2008, the S&P 500 was down 38.5%, but what about financial compensation (salary, bonuses, stock options, etc.) to the 500 CEOs that run the companies? To learn more about the mean CEO compensation, an alphabetical list of the 500 companies was obtained and ordered from 1(3m) to 500 (Zions Bancorp). Next, the random number table was used to select a random number from 1 to 50. The number selected was 10. Then, the companies numbered 10,60,110,160,210, 260, 310, 360, 410, and 460 were investigated and the total CEO c ompensation recorded. The data, stored in CEO are as follows.
Number Company Compensation
10 Aflac 10,783,232
60 Big Lots 9,862,262
110 Comerica 4,108,245
160 EMC 13,874,262
210 Harley-Davison 6,048,027
260 Kohl's 11,638,049
310 Molson Coors Brewing 5,558,499
360 Pfizer 6,629,955
410 Sigma-Aldrich 3,983,596
460 United Parcel Service 5,168,664
A. Construct a 95% confidence interval estimate for the mean 2008 compensation for CEOs of S&P 500 companies.
B. Construct a 99% confidence interval estimate for the mean 2008 compensation for CEOS of S&P 500 c companies
C. Comment on the effect that changing the level of confidence had on your answers in (a) and (b).
In New York State, savings banks are permitted to sell a form of life insurance called savings bank life insurance (SBLI). The approval process consists of underwriting, which includes a review of the application, a medical information bureau check, possible requests for additional medical information and medical exams, and a policy compilation stage in which the policy pages are generated and sent to the bank for delivery. The ability to deliver approved policies to customers in a timely manner is critical to the profitability of this service. During a period of one month, a random sample of 27 approved policies is selected, and the total processing time, in days, is recorded (and stored in Insurance)
73 19 16 64 28 28 31 90 60 56 31 56 22 18
45 48 17 17 17 91 92 63 50 51 69 16 17
a. In the past, the mean processing time was 45 days. At the 0.05 level of significance, is there evidence that the mean processing time has changed from 45 days?
b. What assumption about the population distribution is needed in order to conduct the t test in (a)?
c. Construct a boxplot or a normal probability plot to evaluate the assumption made in (b).
d. Do you think that the assumption needed in order to conduct the t test in (a) is valid? Explain.
a) null hypothesis: mean=45
Alternative hypothesis: mean≠45
this is a two tailed t test.
the degree of freedom is 27-1=26
the critical t values are ±2.06
The expert examines fortune 500 CEO salaries. The large publicly that trades on the New York Stock Exchange are determined.