A forensic psychologist conducted a study to examine whether being hypnotized du
ID: 3321555 • Letter: A
Question
A forensic psychologist conducted a study to examine whether being hypnotized during recall affects how well a witness can remember facts about an event. Nine participants watched a short film of a mock robbery, after which each participant was questioned about what he or she had seen. The five participants in the experimental group were questioned while they were hypnotized and provided accurate responses with M = 15 and S2 = 16. The four participants in the control group gave and provided accurate responses with M = 18 and S2 = 3.33. Using the .05 significance level, do hypnotized witnesses perform differently than witnesses who are not hypnotized? (Hint: Use the five steps of hypothesis testing). A forensic psychologist conducted a study to examine whether being hypnotized during recall affects how well a witness can remember facts about an event. Nine participants watched a short film of a mock robbery, after which each participant was questioned about what he or she had seen. The five participants in the experimental group were questioned while they were hypnotized and provided accurate responses with M = 15 and S2 = 16. The four participants in the control group gave and provided accurate responses with M = 18 and S2 = 3.33. Using the .05 significance level, do hypnotized witnesses perform differently than witnesses who are not hypnotized? (Hint: Use the five steps of hypothesis testing).Explanation / Answer
Solution:-
State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.
Null hypothesis: 1 - 2 = 0
Alternative hypothesis: 1 - 2 0
Note that these hypotheses constitute a two-tailed test. The null hypothesis will be rejected if the difference between sample means is too big or if it is too small.
Formulate an analysis plan. For this analysis, the significance level is 0.10. Using sample data, we will conduct a two-sample t-test of the null hypothesis.
Analyze sample data. Using sample data, we compute the standard error (SE), degrees of freedom (DF), and the t statistic test statistic (t).
SE = sqrt[(s12/n1) + (s22/n2)]
SE = 2.008
DF = 7
t = [ (x1 - x2) - d ] / SE
t = - 1.49
where s1 is the standard deviation of sample 1, s2 is the standard deviation of sample 2, n1 is the size of sample 1, n2 is the size of sample 2, x1 is the mean of sample 1, x2 is the mean of sample 2, d is the hypothesized difference between the population means, and SE is the standard error.
Since we have a two-tailed test, the P-value is the probability that a t statistic having 7 degrees of freedom is more extreme than -1.49; that is, less than -1.49 or greater than 1.49.
Thus, the P-value = 0.18
Interpret results. Since the P-value (0.18) is greater than the significance level (0.10), we cannot accept the null hypothesis.
We can conclude that hypnotized witnesses perform differently than witnesses who are not hypnotized.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.