Exercise 5 – Confidence Intervals
Use the following informa1on for parts 1 through 3:
Mean
31.235
s
5.619
N
20
Use the Exercise 5.sav data set for part 5 of this exercise.
Do the following tasks:
1. Compute the SEM for a confidence interval with σ unknown.
2. You can use the α = 0.05 column in the one-tailed t test to find the two-tailed t value for α =
0.10. Provide the following informa1on for α = 0.10: Degrees of Freedom
tα=0.10
What is the margin of error for α = 0.10?
What is the lower bound for the confidence interval? Upper bound?
3. You need to generate a confidence interval for α = 0.02. Do you expect the lower bound for
the confidence interval to be less than, equal to, or greater than the lower bound for the α
= 0.05 confidence interval? Explain why.
4. Using the Exercise 5.sav data set and SPSS, generate a confidence interval for α = 0.07.
Paste the SPSS output showing the confidence interval and related descrip1ve informa1on
to your report.
Guidelines:
1. Prepare a report with all responses in a MicrosoX Word document.
2. Place your name on the first line of your report.
3. Number your responses based on the task numbers above.
4. Use complete sentences for all responses.
5. Number your pages.
6. When asked to copy an item from SPSS, only copy the requested item.
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7. Name your document lastname-exercise5.doc or lastname-exercise5.docx
8. Submit your work via Canvas.
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