1)

For single-sample statistical tests, you choose a (answer here) test if the population variance is known, and a (answer here) test if the population variance is unknown.

2)

The critical value for a one-tailed one sample z- test is +/-: (answer here)

3)

If the z-score for a sample mean is 1.75, and it was a one-tailed z-test, we(answer here) the null hypothesis.

4)

A researcher reports the results of a single-sample t-test as t(28) = 1.80. The degrees of freedom for this t-test are (answer here), which means there were (answer here) total participants in the researcher's sample.

5)

Based on the information in question #4 above and knowing it is a two-tailed test, the critical t value is: (answer here)