So com/af/servlet/quiz?quiz action-takeQuiz&quiz; probGuid-QNAPCOA80101000000414
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So com/af/servlet/quiz?quiz action-takeQuiz&quiz; probGuid-QNAPCOA80101000000414d8cc0090000&ctx; cansorge-0057&ck; m.15304921 Attempts: Average:/10 AaAa? S. A two-tailed hypothesis test for a repeated-measures design A graduate student is interested in how viewing different kinds of scenery affects working memory. For his study, he selects a random sample of 49 adults. The subjects complete a test of working memory before and after walking in a nature setting Before the walk, the mean score on the test of working memory was 9.4. After the walk, the mean score was 8.5. The mean of the differences between each person's pre- and post- scores was 0.9, with a standard deviation of the differences equal to 1.8. The graduate student has no presupposed assumptions about how viewing different kinds of scenery affects working memory, so he formulates the null and alternative hypotheses as: He uses a repeated-measures t test. Because the sample size is large, if the null hypothesis is true as an equality, the test statistic follows a t-distribution with n-1 49-1 48 degrees of freedom. Degrees of Freedom-55 1.0 2.0 3.0 4.0Explanation / Answer
This is paired t test.
Critical values are +/-2.0106
Reject H0 if t value < -2.0106 or t value > 2.106 (Critical region)
Standard Error = SE = 1.8/sqrt(49) = 0.2571
Test statstic t = 0.9 / 0.2571 =3.5
The t statstic is not in the critical values so the null hypothesis is reject . The graduate student is conclude that vieweing nature scenery affects working memory
Again if SD = 1.4 then
Standard Error = SE = 1.4/sqrt(49) = 0.2
Test statstic t = 0.9 / 0.2 = 4.5
The t statstic is not in the critical values so the null hypothesis is reject . The graduate student is conclude that vieweing nature scenery affects working memory
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