Although many people think they can put a meal on the table in a short period of time, an article reported that they end up spending about 40 minutes doing so. Suppose another study is conducted to test the validity of the statement. A sample of 25 people is selected, and the length of time to prepare and cook dinner (in minutes) is recorded with the following results (in DINNER)
44.0 51.9 49.7 40.0 55.5 33.0 43.4 41.3 45.2 40.7 41.1 49.1 30.9
45.2 55.3 52.1 55.1 38.8 43.1 39.2 58.6 49.8 43.2 47.9 46.6
a) Is there evidence that the population mean time to prepare and cook dinner is different from 40 minutes? Use the p-value approach and a level of significance of 0.05.
b) What assumption about the population distribution is needed in order to conduct the t test in (a)?
c) Make a list of various ways you could evaluate the assumption noted in (b).
d) Evaluate the assumption noted in (b) and determine whether the t test in (a) is valid.