Using techniques from an earlier section, we can find a confidence interval for _d. Consider a random sample of n matched data pairs A, B. Let d = B A be a random variable representing the difference between the values in a matched data pair. Compute the sample mean

d

of the differences and the sample standard deviation s_d. If d has a normal distribution or is mound-shaped, or if n 30, then a confidence interval for _d is as follows.

dE<_d<d+E

where

E=t_c

s_d

n

c= confidence level (0 <c< 1) t_c= critical value for confidence levelcandd.f. =n1

B: Percent increase for company6181618642137A: Percent increase for CEO18303014

4

191530

(a) Using the data above, find a 95% confidence interval for the mean difference between percentage increase in company revenue and percentage increase in CEO salary. (Round your answers to two decimal places.)

lower limit
upper limit