Posted: January 25th, 2016
. Conduct a chi-square test on these data. Report the hypotheses, test statistic, and p-value. Summarize your conclusion
Many songs associate Mondays with having the blues, but are people really more likely to commit suicide on Mondays? A recent study (Kposowa et al., 2009) analyzed data on suicides in the United States between the years 2000 and 2004. They classified each suicide according to the day of the week on which it occurred. Their data produced the following sample percentages:
A news article that described this study did not report the sample size. Suppose for now that the sample size was . The computer output below presents results of a chi-square goodness-of-fit test of equal proportions:
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a. Explain how the expected counts were calculated.
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Seven is divided by the sample size. |
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The sample size is divided by percentage of suicides for each day. |
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The percentage of suicides for each day is divided by the sample size. |
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The sample size is divided by seven. |
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The percentage of suicides for each day is multiplied by the sample size. |
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c. Interpret what the -value means in this context.
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d. Summarize the conclusion that you would draw from this -value.
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You have no statistical evidence that the probability of a suicide occurring on any of the seven weekdays is not the same. |
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You have weak statistical evidence that the probability of a suicide occurring on any of the seven weekdays is not the same. |
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You have strong statistical evidence that the probability of a suicide occurring on any of the seven weekdays is not the same. |
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e. Which day appears to be especially likely for suicides?
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f. If the sample size were larger, and the sample percentages stayed the same, how would the -value change?
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Unit 6, Topic 25, Exercise 25-22
Attachments:
exercise_25-22.pdf
Many songs associate Mondays with having the blues, but are people really more likely to commit suicide on Mondays? A recent study (Kposowa et al., 2009) analyzed data on suicides in the United States between the years 2000 and 2004. They classified each suicide according to the day of the week on which it occurred. Their data produced the following sample percentages:
A news article that described this study did not report the sample size. Suppose for now that the sample size was . The computer output below presents results of a chi-square goodness-of-fit test of equal proportions:
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a. Explain how the expected counts were calculated.
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Seven is divided by the sample size. |
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The sample size is divided by percentage of suicides for each day. |
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The percentage of suicides for each day is divided by the sample size. |
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The sample size is divided by seven. |
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The percentage of suicides for each day is multiplied by the sample size. |
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b. Choose how the chi-square contribution for Monday was calculated.
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c. Interpret what the -value means in this context.
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d. Summarize the conclusion that you would draw from this -value.
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You have no statistical evidence that the probability of a suicide occurring on any of the seven weekdays is not the same. |
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You have weak statistical evidence that the probability of a suicide occurring on any of the seven weekdays is not the same. |
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You have strong statistical evidence that the probability of a suicide occurring on any of the seven weekdays is not the same. |
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e. Which day appears to be especially likely for suicides?
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f. If the sample size were larger, and the sample percentages stayed the same, how would the -value change?
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Unit 6, Topic 25, Exercise 25-22