8. 9. Suppose X has a normal distribution. It you do not know the population standard deviation and you want to estimate the mean ol the population. what do you use? a. Use the sample standard deviation. b. Use the t-distribution c. Both a and b are correct. Suppose you want to make a condence interval for the mean and X has a normal distribution. but you don't know the population standard deviation. What is the penalty you have to pay for using the SAMPLE standard deviation and not the POPULATION standard deviation? You use a t value that is than 2, making the condence interval a. Bigger. wider b. Smaller. narrower c. Bigger. narrower d. Smallen wider There is only one tdistribution and you use it for all different values of n. a. True b. False The t-distribution is flatter than the Zdistribution. a. True b. False For the same area you will have afthe tvalue. compared to the Zvalue. a. Bigger b. Smaller c. Same The larger is. the closer the t-distribution looks to the one and only Idistribution. a. n b. p c. s d. H To estimate the population mean when you don't know the population standard deviation, use the formula that contains t with degrees of freedom. a. H b. n+1 c. n1 d. 0 which value at t do you need on the ttable it you are doing a 95% condence interval [or the population mean, you don't know the population standard deviation' and n is 20? a. 2.0860 b. 2.0?96 c. 2.0930 d. None of these answers is correct. If you do a hypothesis test for the mean and you used a ttest instead of a test involving 2, and everything else remained the same, your pvalue for the Heat would be compared to the p-vaiue for the test involving 2. a. Smaller b. The same c. Larger 10. Suppose you did a ONE TAILED t-test and the test statistic was 1.50. and the degrees oi freedom for the test was 10 1 = 9. your ovalue is between what two numbers. according to the ttable? a. .1 and .05 b. .05 and .025 c. .15 and .10 d. None of these answers is correct