A recent study revealed the typical American coffee drinker consumes an average of 3.1 cups per day. A sample of 12 senior citizens revealed they consumed the following amounts of coffee, reported in cups, yesterday. 3.1, 3.3 ,3.5 ,2.6, 2.6, 4.3, 4.4 ,3.8 ,3.1 ,4.1 ,3.1, 3.2
(a) State the null hypothesis and the alternate hypothesis. (Round your answers to 1 decimal place.)
(b) State the decision rule for 0.05 significance level. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)
(c) Compute the value of the test statistic. (Round your answer to 3 decimal places.)
(d) Do these sample data suggest there is a difference between the national average and the sample mean of the senior citizens?