Choose a true statement on the two sample test. A.) When testing the difference
ID: 3305325 • Letter: C
Question
Choose a true statement on the two sample test.
A.) When testing the difference between two population proportions, a pooled proportion is calculated ONLY when the population proportions are known.
B.) When testing the difference between two population proportions, it is necessary to use the same size sample from each population.
C.) When using independent samples to test the difference between two population means, a pooled standard deviation is used if the population standard deviations are unknown and assumed equal.
D.) In comparing the means of two independent samples, if the test statistic indicates a significant difference at a=.05, it will also be significant at a = .01.
E.) A paired t-test (for dependent samples) with two columns of 10 observations in each column would use degrees of freedom (df) = 18.
Explanation / Answer
(C) is correct, i.e When using independent samples to test the difference between two population means, a pooled standard deviation is used if the population standard deviations are unknown and assumed equal. Acualy this is the case of compair of mean and the statistics would be follow t-distribution with df (n+m-2).