14. (0.5 + 2 + 1 + 0.5 = 4 marks) A medical researcher suspects that the consumption of alcohol results in increase of reaction time to respond to a given stimulus. To test his hypothesis about the effect of alcohol on reaction time, a researcher selects random sample of seven people, and measures their reaction times before and after drinking 3 ounces of 40% alcohol. Do the following data indicate that the mean reaction time before consuming alcohol was smaller than the mean reaction time after consuming alcohol? Person | Reaction time Reaction time d? before using alcohol after using alcohol s | 4 0 0z Test appropriate hypothesis using a paired- difference test ata = (.05 . Assume that populations of reaction times to a given stimulus before and after drinking alcohol are normal. a. State null and research hypotheses about the mean of population of differences A, = 4L, H\": M b. Calculate the value of the sample mean d for the sample differences, the value of sample standard deviation P for the sample differences, and observed value of test statistic [ obs.* - Il L I I c. State the rejection region (in the form of inequality) d. Insert the word sufficient or insufficient into the following statement. There is sample evidence ata = 0.05to conclude that the mean reaction time after consuming alcohol was greater than the mean reaction time before consuming alcohol