Stats18 Essay Example | Topics and Well Written Essays - 1250 words

Stats18 - Essay Example Answer True False   Question 5    Measures of effect size, such as r2 or Cohen's d, are not greatly influenced by sample size. Answer True False Question 6    Measures of effect size, such as r2 or Cohen's d, are not greatly influenced by sample variance. Answer True False   Question 7    Which of the following is a major difference between a hypothesis test with the t statistic formula and the test with a z-score? Answer a. You must calculate the sample variance (or standard deviation) for the t statistic but not for the z-score. b. You must know the population variance (or standard deviation) for the z-score but not for the t statistic. c. You use the unit normal table to find critical values for the z-score test but not for the t test. d. All of the other options are major differences.   Question 8    If two samples are selected from the same population, under what circumstances will the two samples have exactly the same t statistic? Answer a. If the sample size ( n) is the same for both samples. b. If the samples are the same size and have the same mean. c. If the samples are the same size and have the same mean and have the same sample variance d. None of the other options are correct.   Question 9    A sample of n = 4 scores has SS = 48. What is the variance for this sample? Answer a. 12 b. 16 c. 4 d. 2   Question 10    A sample of n = 9 scores has SS = 72. What is the estimated standard error for the sample mean? Answer a. 9 b. 3 c. 1 d. cannot answer without knowing the sample mean   Question 11    Which set of sample characteristics is most likely to produce a significant t statistic? Answer a. a large sample size and a small sample variance b. a large sample size and a large sample variance c. a small sample size and a small sample variance d. a small sample size and a large sample variance   Question 12    A sample of n = 4 scores has SS = 48. What is the estimated standard error for this sample? Answer a. 12 b. 16 c. 4 d. 2   Question 13    When n is small (less than 30), the t distribution ____. Answer a. is almost identical in shape to the normal z distribution b. is flatter and more spread out than the normal z distribution c. is taller and narrower than the normal z distribution d. cannot be specified, making hypothesis tests impossible   Question 14    With ? = .01, the two-tailed critical region for a sample of n = 20 subjects would have boundaries of ____. Answer a. t =  ±2.845 b. t =  ±2.528 c. t =  ±2.539 d. t =  ±2.861   Question 15    As sample size increases ____. Answer a. the value of df also increases b. the t distribution becomes more like a normal distribution c. the critical values of t become smaller d. All of the other options are true as sample size increases.   Question 16    Two samples from the same population both have n = 10 scores with M = 45. If the t statistic is computed for each sample, then ____. Answer a. the two t statistics will be identic al b. the sample with the larger variance will produce the larger t statistic c. the sample with the smaller variance will produce the larger t statistic d. There is no way to predict the relationship between the two t statistics.   Question 17    In a hypothesis test using a t statistic, what is the influence of using a large sample? Answer a. A larger sample tends to lower the likelihood of rejecting the null hypothesis. b. A larger sample