1. )A researcher is testing the effect of marijuana use on reaction time. A samp
ID: 3242984 • Letter: 1
Question
1. )A researcher is testing the effect of marijuana use on reaction time. A sample of n = 9 students is obtained and each student is given a dose of marijuana. Thirty minutes later, each student's reaction time is measured in a driving simulator. The scores for the sample of students averaged M = 211 milliseconds with SS = 1152. Assuming that reaction time for students in the regular population averages = 200 milliseconds, are the data sufficient to conclude that the medication has a significant effect on reaction time? Test at the .05 level of significance. Which of the four options below is the best answer? Type the letter “A” or “B” etc. in the box
Option A. Accept the null, marijuana has no effect on reaction time
Option B. Accept the null, marijuana does affect reaction time
Option C. Reject the null, marijuana has no effect on reaction time
Option D. Reject the null, marijuana does affect reaction time
2. ) Compute r2, the percentage of variance explained by the treatment effect. (Round the answer to three decimal places.) r2 =
3.) Is this a small, medium, or large effect size? Type “small” , “medium”, or “large” in the box
4. ) A researcher is interested in comparing the sample of inmates’ level of impulsivity to the general population’s average level. The researcher has both the sample mean (M = 33.49) and the population mean (µ = 31.7) for the impulsivity test. The population standard deviation is = 2.75. Which test is correct, the single-sample t-test or the z-score test? Why?
Explanation / Answer
Answer to question# 1)
Sample size n = 9
M = 211
SS = 1152
.
Population Mean Mu =200
.
SE = sqrt (SS/n-1)
SE = sqrt(1152 /8) = 12
.
The formula of test statistic is:
t = (M - Mu) / SE
t = (211 -200) / 12
t = 0.92
.
P value for t = 0.92 and df = n-1 = 9-1 = 8 will be 0.1922
,
Inference: Since the P value 0.1922 > 0.05 signifcance level , we fail to reject the null
thue the repsonse time is same before and after
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