1. It is thought that not as many Americans buy presents to celebrate Valentine's Day anymore. A random sample of 4000 Americans yielded 2200 who bought their significant other a present and celebrated Valentine's Day. Estimate the true proportion of all Americans who celebrate Valentine'sDay using a 90% confidence interval. Express the answer in the form p E and round to the nearest ten-thousandth. 2. Suppose you want to test the claim that = 3.5. Given a sample size of n = 36 and a level of significance of a=0.05 when should you reject H 0 ? 3. A local tennis pro-shop strings tennis rackets at the tension (pounds per square inch) requested by the customer. Recently a customer made a claim that the pro-shop consistently strings rackets at lower tensions, on average, than requested. To support this claim, the customer asked the pro shop to string 7 new rackets at 42 psi. Suppose the two-tailed P-value for the test described above (obtained from a computer printout) is 0.08 Give the proper conclusion for the test. Use a=0.10 4. Suppose you want to test the claim that < 65.4. Given a sample size of n = 35 and a level of significance of a=0.05 when should you reject H 0? 5. Let t 0 be a specific value of t. Find t 0 such that the statement is true: P(t t 0) = 0.01 where df = 20