t-test statistics (Chapter 10)
Use the following data to answer questions 1-6
An elementary school nurse is looking for ways to increase the amount of time students spend washing their hands after using the bathroom. In order to encourage hand washing she posts a sign in the boys' bathroom that says "Remember to wash your hands." In a second (girls') bathroom she posts the same sign but also includes pictures of hand washing.
The scores shown represent the number of seconds that students spend washing their hands.
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Sign Only
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Sign and pictures
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8
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12
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6
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12
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4
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6
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6
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10
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1)What type of t-test does this represent?
2)What is df for this test?
3)If we use a 2-tailed test with a = .05, what is the critical t-value?
4)if we use a 1-tailed test with alpha = .01, what is the critical t-value?
5)Calculate the t-test score using the correct formula.
6)Can we conclude that using a sign with pictures is more effective than a sign with words alone? Explain.
7. In a sample with n = 10, what is the critical t table score for a 2 directional test with a = .05?
8. In a sample with n = 25, what is the critical t table core for a one directional test with a =.05?