A significance test is to be conducted concerning population

A significance test is to be conducted concerning population means mu1 and mu2 based on the difference between two sample means: x1bar-x2 bar. What assumptions are required in order for the two-sample z statistic to be valid? a The two samples must be independent. b. The two samples must be simple random samples. c. The variable must be Normally distributed in the two populations. d. All of the above e. None of these are necessary provided we have a large sample size.

Solution

For the two sample z test to be valid, The samples must ne independent, these samples must be simple random samples, and the population from which samples are drawn must follow Normal distribution.

Hence the correct option is d) All of the above