A researcher hypothesizes that caffeine will affect the speed with which people read. To test this,...

A researcher hypothesizes that caffeine will affect the speed with which people read. To test this, the researcher randomly assigns 8 people into one of two groups: 50mg Caffeine (n1=4) or no Caffeine (n2=4). An hour after the treatment, the 8 participants in the study are asked to read from a book for 1 minute; the researcher counts the number of words each participant finished reading. The following are the data for each group:

50mg Caffeine (group 1)

450 400 500 450

No Caffeine (group 2)

400 410 430 440

Use α-level of .05 to answer the questions below:

i. Draw the sampling distribution of the difference between independent sample means, and locate M1-M2, μ(m1-M2) on the x-axis. What is the value of μ(m1-M2 under the assumption of the null hypothesis; indicate this on the x-axis as well.

j. Given the total df for this problem, what is the critical value of t? Indicate the critical value of t (and its value) in your drawing on (i). Also, indicate what the area is in the tail beyond the critical value of t.

k. Can you reject the null hypothesis?

l. Can you accept the research hypothesis?

Solutions

Expert Solution

milcah answered 2 hours ago

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