78

(a) For Company A, is the increase in the satisfaction score from year 1 to year 2 statistically significant? Use α = 0.05.  (Let μ1 = the satisfaction score for year 2 and μ2 = the satisfaction score for year 1.)

H0: μ1 − μ2 ≤ 0

Ha: μ1 − μ2 > 0

p

75.3α

H0: μ ≤ 75.3

Ha: μ > 75.3

p

(c) For Company B, is the increase from year 1 to year 2 statistically significant? Use α = 0.05. (Let μ1 = the satisfaction score for year 2 and μ2 = the satisfaction score for year 1.)

H0: μ1 − μ2 ≤ 0

Ha: μ1 − μ2 > 0

p

(d) When conducting a hypothesis test with the values given for the standard deviation, sample size, and α, how large must the increase from year 1 to year 2 be for it to be statistically significant? (Round your answer to two decimal places.) = ?