A researcher conditions rats to fear a tone that was sounded just prior to a brief shock.To measure fear following this conditioning,she records the number of lever presses by each rat in the presence and in the absence of the tone.It was hypothesized that reduced lever pressing in the presence of the tone was evidence for a conditioned fear response in rats.If the researcher tested this hypothesis at a .05 level of significance (two-tailed test),then what is her decision if she computes t = ñ2.842 in a sample of 8 rats.
A)Retain the null hypothesis;there is evidence for a conditioned fear response.
B)Retain the null hypothesis;there is not evidence for a conditioned fear response.
C)Reject the null hypothesis;there is evidence for a conditioned fear response.
D)Reject the null hypothesis;there is not evidence for a conditioned fear response.

Question

Quizplus · Accepted Answer

The computed t-value of -2.842 falls in the rejection region of the t-distribution with 7 degrees of freedom at the .05 level of significance for a two-tailed test. Therefore, the null hypothesis of no conditioned fear response can be rejected, and there is evidence for a conditioned fear response in the rats.

A Researcher Conditions Rats to Fear a Tone That Was