Problem 12E

Corporate sustainability of CPA firms. Corporate sustainability refers to business practices designed around social and environmental considerations. Refer to the Business and Society (March 2011) study on the sustainability behaviors of CPA corporations, Exercise 2.23 (p. 59). Recall that the level of support for corporate sustainability (measured on a quantitative scale ranging from 0 to 160 points) was obtained for each in a sample of 992 senior managers at CPA firms. Higher point values indicate a higher level of support for sustainability. The accompanying Minitab printout gives a 90% confidence interval for the mean level of support for all senior managers at CPA firms.

a. Locate the 90% confidence interval on the printout.

b. Use the sample mean and standard deviation on the printout to calculate the 90% confidence interval. Does your result agree with the interval shown on the printout?

c. Give a practical interpretation of the 90% confidence interval.

d. Suppose the CEO of a CPA firm claims that the true mean level of support for sustainability is 75 points. Do you believe this claim Explain.

Solution:

Step 1 of 5:

The summary of the data regarding level of support for corporate sustainability for each seniors managers in CPA firms in a sample of 992 managers is given as

Variable |
N |
Mean |
St.Dev |
SE.Mean |
90% C.I |

Support |
992 |
67.755 |
26.871 |
0.853 |
(66.350,69.160) |

Using this we need to find the required values.