Sleep for Med Students vs. Non Med Students
One-Tailed and Two-Tailed Tests
Consider the sleep habits of med students versus non med students. The study consists of the hours of sleep per day obtained by 25 med students and 30 non-med students. The summarized data is given in the table below. x-bar is the mean hours of sleep per day from each sample. The degrees of freedom is given to save calculation time if you are not using software.
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Mean Sleep Per Night for Med Students vs. Non-Med Students
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Type of Student
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n
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s2
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s
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Med Student (x1)
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25
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5.7
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0.9
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0.95
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Non Med Student (x2)
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30
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6.3
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1.9
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1.38
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Degrees of Freedom: df = 51
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1) The Two-Tailed Test:
Test the claim that the mean number of hours of sleep for med and non med students is different. Use the 0.05 significance level.
a. What is the claim?
b. What are the null hypothesis and alternative hypotheses?
c. What test statistic did you obtain? Hint: this is a t-test. Make sure you show your work.
d. Would you reject or fail to reject the null hypothesis? Why? Make sure you are not using generic wording. Which specific hypothesis test are you rejecting or failing to reject?
e. Conclusion: Is there enough data to support the claim that the mean hours of sleep by med and non med students are different?
2) The Two-Tailed Test:
Test the claim that the mean number of hours of sleep for med and non med students is different. Use the 0.01 significance level.
a. What is the claim?
b. What are the null hypothesis and alternative hypotheses?
c. What test statistic did you obtain? Hint: this is a t-test. Make sure you show your work.
d. Would you reject or fail to reject the null hypothesis? Why? Make sure you are not using generic wording. Which specific hypothesis test are you rejecting or failing to reject?
e. Conclusion: Is there enough data to support the claim that the mean hours of sleep by med and non med students are different?
3) The One-Tailed Test:
Test the claim that, on average, med students get LESS sleep than non-med students. Use the 0.05 significance level.
a. What is the claim? Is this a left-tailed test, a right-tailed test, or a non-directional test?
b. What are the null hypothesis and alternative hypotheses?
c. What test statistic did you obtain? Hint: this is a t-test. Make sure you show your work.
d. Would you reject or fail to reject the null hypothesis? Why? Make sure you are not using generic wording. Which specific hypothesis test are you rejecting or failing to reject?
e. Conclusion: Is there enough data to support the claim that, on average, med students get less sleep than non-med students?
4) The One-Tailed Test:
Test the claim that, on average, med students get LESS sleep than non-med students. Use the 0.01 significance level.
a. What is the claim? Is this a left-tailed test, a right-tailed test, or a non-directional test?
b. What are the null hypothesis and alternative hypotheses?
c. What test statistic did you obtain? Hint: this is a t-test. Make sure you show your work.
d. Would you reject or fail to reject the null hypothesis? Why? Make sure you are not using generic wording. Which specific hypothesis test are you rejecting or failing to reject?
e. Conclusion: Is there enough data to support the claim that, on average, med students get less sleep than non-med students?