# Test for Single Samples

1. A cognitive psycholgist believes that a particular drug improves short-term memory. The drug is safe, with no side effects. An experiment is conducted in which 8 ramdomly selected subjects are given the drug and then given a short time to memorize a list of ten words. The subjects are then tested for retention 15 minutes after the memorization period. The number of words correctly recalled by each subject is as follows: 8,9,10,6,8,7,9,7. Over the past few years, the psychologist has collected a lot of data using this task with similar subjects. Although he has lost the original data, he remembers that the mean was 6 words correctly recalled and that the data were normally distributed. On the basis of these data, what can we conclude about the effect fo the drug on short term memory? Use alpha = 0.05 two tail in making your decisison.

Please assist on solving this problem using the "t" test for single samples.

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#### Solution Preview

Ho: M = 6

Ha: M > 6

Firstly we compute the mean of the eight samples:

Xm = SUM(X) / 8 = 8

The variance is ...

#### Solution Summary

1. A cognitive psycholgist believes that a particular drug improves short-term memory. The drug is safe, with no side effects. An experiment is conducted in which 8 ramdomly selected subjects are given the drug and then given a short time to memorize a list of ten words. The subjects are then tested for retention 15 minutes after the memorization period. The number of words correctly recalled by each subject is as follows: 8,9,10,6,8,7,9,7. Over the past few years, the psychologist has collected a lot of data using this task with similar subjects. Although he has lost the original data, he remembers that the mean was 6 words correctly recalled and that the data were normally distributed. On the basis of these data, what can we conclude about the effect fo the drug on short term memory? Use alpha = 0.05 two tail in making your decisison.

Please assist on solving this problem using the "t" test for single samples.