Question

From her firm's computer telephone log, an executive found that the mean length of 67 telephone calls during July was 4.32 minutes with a standard deviation of 5.14 minutes. She vowed to make an effort to reduce the length of calls. The August phone log showed 49 telephone calls whose mean was 2.090 minutes with a standard deviation of 2.766 minutes. (a) Choose the appropriate hypotheses for a right-tailed test. Assume µ1 is the average call length in July and µ2 is the average call length in August. a. H0: μ1 – μ2 ≤ 0 vs. H1: μ1 – μ2 > 0 b. H0: μ1 – μ2 < 0 vs. H1: μ1 – μ2 ≤ 0 a b (b-1) Obtain a test statistic tcalc and p-value assuming unequal variances. (Use the quick rule to determine degrees of freedom. Round your answers to 3 decimal places.) tcalc p-value (b-2) Interpret the results using α = .01. the null hypothesis. (b-3) What is your conclusion at α = .01? We conclude the length of calls had been reduced.

Answer 1