When Do Researchers Use T Distributions and the Family of T

Multiple Choice

When do researchers use t distributions and the family of t tests to seek support for a relationship between variables rather than simply computing confidence intervals based on the normal distribution (as described in Chapter 5) ?

A) When the mean of the dependent variable within the research sample is not known.
B) When the mean of the dependent variable within the population is badly skewed.
C) When the standard deviation of the dependent variable within the population is not known.
D) When the dependent variable is less than interval level.