Question

To An independent-measures t hypothesis test is appropriate when the value for a is known a. b. the mean for a treated group of subjects is compared to a known population mean C. one sample is used to test a hypothesis about one population P there are two separate samples containing different subjects 17. One sample of n 5 scores has a variance of s 10 and a second sample of n= 10 scores has s pooled variance is computed for these two samples, then the value obtained will be closer to 10 than to 20 b. closer to 20 than to 10 -20. If the a. exactly half way between 10 and 20 c. d. cannot be determined without more information 18. As the sample variance increases, the value of the t statistic increases (moves away from zero) b. decreases (moves toward zero) c. approximates the value of Mi - M2 d. the value oft is not influenced by sample variance a. Assuming that there is a 5-point difference between the two sample means, which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic? nin2 25 and small sample variances b. a. 25 and large sample variances ni n= n n2 = 100 and small sample variances d. nin2 = 100 and large sample variances с. 197

Answer 1

16 (d) An independent measure t test is appropriate when there are 2 separate samples containing unrelated groups as this test is usually used to determine if there is statistically significant difference between 2 unrelated groups.

17 (b) The pooled variance is given by [(n1-1)* V1 + (n2-1)*V2] / [n1+n2-2] = [(5-1)* 10 + (10-1)*20] / [5+10-2]

= (40+180) / 13 = 220/13 = 17 roughly

Which is closer to 20 than 10

18 (b) As the sample variance increases the denominator increases, decreasing the t statistic and hence it moves towards 0.

19 (a) To be more likely to produce a significant value of the t statistic the t statistic has to be higher, which would require the denominator or the pooled variance to be lower which would require lower n1 and n2 (also lower n1 and n2 would lower the critical cutoff point for the t distribution) and lower variance.