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The estimated standard deviation of the distribution of differences is used to predict the: a. standard error of the mean c. standard error of the estimate b. standard error of the difference d. actual standard score The estimated standard error of difference may be obtained on the basis of the 40. information contained in: a. a single sample c. the sampling error b. a pair of random samples d. a single z score 41. When pairs of samples are selected from two separate populations, the mean of the distribution of differences is assumed to be: a. some value other than zero c. a constant b. zero d. equal to the means of the distribution means 42. The independent t test may be used to evaluate the difference between: a. two sample means c. the mean and the standard deviation b. two or more sample means d. the mean and the variance 43. For the independent t test, the null hypothesis states that the samples: a. represent a single population c. are of infinite size b. two samples represent different populations d. each have means scores of zero 44. For the independent t test, degrees of freedom are based on: a. the population sizes c. the number of samples being compared b. the sample sizes d. none of these 45. For the independent t test, the hypothesis of "no difference" is called the: a. alternative hypothesis c. Central Limit theorem b. null hypothesis d. hypothesis of association 46. When a difference is considered "significant", it indicates that the difference is probably: a. meaningful and profound c. not due to chance alone b. due to chance and chance alone d. none of these 47. The difference between the T score and the t ratio is that: a. the T score always results in a higher value than does the t ratio b. the T score refers to several sample means, whereas the t ratio only refers to two sample means c. the T score is used as a measure of individual performance, whereas the t ratio evaluates the possibility of a performance difference between the two groups d. none of these, since T and t are the same 48. The statement that the difference between the two population means is zero, represents: a. the alpha error b. the sampling error c. the alternative hypothesis d. the null hypothesis 49. The alpha error is identical to the: a. Type 1 error b. Type 2 error c. Type 3 error d. none of these