Question

Loftus and Palmer studied the relationship between implicit recall cues and memory. They manipulated the wording in questioning subjects about an accident they had viewed on film. Students were shown a multi-car accident and then given a questionnaire asking them to recall details of the collision. One group of subjects were asked to estimate how fast the cars were travelling when they "hit" each other, while the other group was asked to estimate how fast the cars were travelling when they "smashed" into each other. You are asked to determine whether the wording influenced their recollections. The following estimates were obtained. Smashed: 22, 20, 20, 17, 18, 26, 26, 19, 18, 22, 24, 18 Hit: 24, 15, 17, 21, 17, 14, 16, 18, 21, 17, 22, 19, 14, 19, 23 a.) Should alpha be one-or two-tailed? Why? b.) Test the hypothesis at the .05 level.

Answer 1

Let denote the average speed of cars when they "hit" each other and when they "smashed" into each other respectively.

Part a.

To test Null hypothesis

against

This is a two tailed test.

Part b.

Using Excel Output:

The value of the test statistic

and critical value

Since ,

So we will fail to reject H₀ at 5% level of significance and we can conclude that there is not enough evidence to support the claim that the wording influenced their recollections.

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