Question

An important statistical measurement in service facilities (such as restaurants and banks) is the variability in service times. As an experiment, two bank tellers were observed, and the service times for each of 100 customers were recorded. Do these data allow us to infer at the 5% significance level that the variance in service times differs between the two tellers? Estimate with 95% confidence the ratio of variances of the two bank tellers. Teller 1 Teller 2 7.2 10.9 5.4 6.0 3.7 6.7 6.4 8.3 11.2 14.3 8.7 3.7 9.3 7.6 6.9 8.0 9.1 8.1 8.6 1.3 7.3 10.6 6.1 8.0 6.7 10.8 4.4 10.5 7.4 9.7 7.6 3.6 8.9 7.3 10.9 7.8 7.2 4.4 4.2 4.0 10.5 7.9 9.3 12.5 8.2 6.2 5.8 10.3 7.2 8.0 7.0 4.3 6.1 10.4 9.1 7.6 8.1 11.3 9.4 6.5 8.4 13.4 10.1 10.0 8.1 3.5 5.6 6.5 6.2 9.0 7.3 10.6 9.9 5.9 5.9 14.5 8.1 4.7 8.4 2.2 7.3 7.1 7.7 5.3 9.1 4.1 8.4 5.2 7.8 13.5 10.1 10.5 10.0 10.8 4.4 9.4 7.7 2.3 6.9 12.2 8.8 12.0 7.7 8.1 7.9 5.2 7.1 7.0 8.3 5.4 12.3 5.3 10.6 3.1 11.4 6.6 8.4 10.9 7.3 8.1 6.8 10.1 10.7 7.9 8.5 4.5 7.2 10.2 6.9 14.8 9.8 6.0 9.4 7.1 7.8 15.2 7.5 8.3 6.4 7.4 7.4 12.9 11.3 1.9 9.7 7.3 9.2 4.7 8.8 6.4 8.0 10.5 3.5 8.3 7.4 5.7 7.9 3.4 7.2 5.4 9.9 7.6 6.1 4.4 3.5 6.9 6.1 5.7 9.9 12.0 10.7 9.2 7.4 5.7 8.3 6.5 8.1 7.6 5.1 12.9 11.0 7.3 7.0 15.6 8.1 4.2 4.8 10.3 8.7 11.9 9.6 9.1 9.3 6.5 6.3 0.1 6.4 9.1 7.8 4.7

Answer 1