The main difference between a Z score and a t score is that: Question 1 options: t scores are used when a study is analyzed with a one-tailed test. t scores are used when the population variance is unknown. t scores are used only when the sample size is greater than 30. t scores are used only when inferences are made about other samples. Question 2 (2.5 points) Listen When estimating the variance of a population from the sample, the sample variance cannot be used directly because: Question 2 options: it is based on using absolute deviations. it is based on using squared deviations. it tends to be slightly too largeit overestimates the population variance. it tends to be slightly too smallit underestimates the population variance. Question 3 (2.5 points) Listen When figuring the pooled population variance estimate in a t test for independent means: Question 3 options: the variance of at least one of the original populations must be known, as opposed to estimated, but the other can be estimated from sample scores. the variance of BOTH of the original populations must be known, as opposed to estimated. the estimates based on each of the samples are averaged in such a way as to give more influence to the estimate based on more participants. the scores from both samples are combined to form a single sample, and the estimated variance is figured in the usual way using this combined sample. Question 4 (2.5 points) Listen A social psychologist interested in