In this problem, assume that the distribution of differences is
approximately normal. Note: For degrees of freedom
d.f. not in the Student's t table, use
the closest d.f. that is smaller. In
some situations, this choice of d.f. may increase
the P-value by a small amount and therefore produce a
slightly more "conservative" answer.
Are America's top chief executive officers (CEOs) really worth all
that money? One way to answer this question is to look at row
B, the annual company percentage increase in revenue,
versus row A, the CEO's annual percentage salary increase
in that same company. Suppose a random sample of companies yielded
the following data:
B: Percent
increase for company |
30 | 22 | 22 | 18 | 6 | 4 | 21 | 37 |
A: Percent
increase for CEO |
16 | 14 | 24 | 14 | -4 | 19 | 15 | 30 |
Do these data indicate that the population mean percentage increase in corporate revenue (row B) is different from the population mean percentage increase in CEO salary? Use a 5% level of significance. Solve the problem using the critical region method of testing. (Let d = B − A. Round your answers to three decimal places.)
test statistic | = | |
critical value | = |
here we want to test the
null hypothesis H0:=0 ( increase in corporate revenue is same)
alternate hypothesis Ha: ( increase in corporate revenue different or not same)
we use paired t-test and statisitc t=/sd/(sqrt(n))=4/(8.9602/sqrt(8))=1,2627 with n-1=8-1=7 fg
critical t=t(0.05/2,7)=2.3646
since the calculated t=1.2627 is less than critical t=2.3646, so we fail to reject H0(or accept H0) and conclude that increase in corporate revenue same or not different.
B | A | d=B-A |
30 | 16 | 14 |
22 | 14 | 8 |
22 | 24 | -2 |
18 | 14 | 4 |
6 | -4 | 10 |
4 | 19 | -15 |
21 | 15 | 6 |
37 | 30 | 7 |
n= | 8 | |
mean= | 4.0000 | |
sd= | 8.9602 | |
SE=sd/sqrt(n)= | 3.1679 | |
t= | 1.2627 | |
critical t= | 2.3646 | |
two tailed | p-value= | 0.2471 |
one tailed | p-value= | 0.1236 |
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