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Another confidence interval problem


New member
Oct 24, 2009
For a group of 10 men subjected to a stress situation, the mean number of heartbeats per minute was 126 and the sample standard deviation was 4.

What is the margin of error for a 95% confidence interval?

What is the 95% confidence interval of the true mean?

Write a sentence explaining the 95% confidence interval in context of the question. (There are only a few ways to do this correctly, so be sure to read the book closely.)

Write a few sentences explaining what would happen if you wanted a 90% confidence interval?

Write a few sentences explaining what would happen if you changed the sample size to be 1000 men and kept a 95% confidence interval.


Staff member
Apr 12, 2005
You're not even going to try? Give us a confidence interval formula or something... Show us the relationship between a Standard Deviation and a Sample Standard Deviation.