Hypothesis Testing: Two Independent Samples - Prof. Animikh Biswas, Exams of Statistics

Download Hypothesis Testing: Two Independent Samples - Prof. Animikh Biswas and more Exams Statistics in PDF only on Docsity! Stat 1222. Professor: Dr. A. Biswas Hypothesis Testing: Two Independent Sample (Large) 1. A professor wanted to study the effect of using a computer program to teach statistics. In her first class of 43 students, she used the computer as an instructional aid in class. In her second class of 35 students, she taught without the computer. On the common final exam, the first class scored a mean of 78.32, with a standard deviation of 8.07; while the second class scored a mean of 80.41, with a standard deviation of 8.53. Test if the use of the computer makes any difference in mean scores. (a) Set up the null and alternative hypotheses. (b) Find the value of the standardized test statistic. (c) Find the rejection region at 5% significance level. State your conclusion in the context of the problem. (d) Find the P-value for this test. Based on the P-value, what is your conclusion at 5% signif- icance level? At 1% significance level? 2. A pharmaceutical company wants to test Dozenol, a new cold medicine intended for night use. Tests for such products often include a “treatment group” of people who use the drug, and a “control group” of people who do not use the drug. Fifty people with colds are given Dozenol, and 100 others are not. The systolic blood pressure is measured for each subject, and the sample statistics are summarized below: Treatment group Control group n1 = 50 n2 = 100 x̄1 = 203.4 x̄2 = 189.4 s1 = 39.4 s2 = 39.0