Nonexperimental studies always contain a threat to internal validity, which means that these studies cannot establish unambiguous cause-and-effect relationships.

It is possible for a distribution of scores to have more than one ____.

Who determines the type of local anesthetic agent and strength the patient receives in a procedure? 

In a distribution with a mean of M = 36 and a standard deviation of SD = 8, a score of 40 would be considered an extreme value.

A researcher comparing depression scores before and after treatment in one group of clients, is using a(n) ____.

A researcher reports a significant correlation using an alpha level of .01. The probability that the researcher is making a Type I error is p < .01.

One advantage of a factorial research design is that is creates a more realistic situation in which to observe the relationship between variables.

The Pearson correlation is used when both scores are _____.

In an experiment, the purpose for manipulating the independent variable is to help ____.

In which research situation below would an extraneous variable become a confounding variable?