Fowle marketing research, inc., bases charges to a client on the assumption that telephone surveys can be completed in a mean time of 15 minutes or less. if a longer mean survey time is necessary, a premium rate is charged. suppose a sample of 35 surveys
provided the following survey times in minutes: 17; 11; 12; 23; 20; 23; 15; 16; 23; 22; 18; 23; 25; 14; 12; 12; 20; 18; 12; 19; 11; 11; 20; 21; 11; 18; 14; 13; 13; 19; 16; 10; 22; 18; 23.
based upon past studies, the population standard deviation is assumed known with σ = 4 minutes.
1. is the premium rate justified? a. formulate the null and alternative hypotheses for this application. b. compute the value of the test statistic. c. what is the p-value? d. at a = .01, what is your conclusion?