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# Confidence Intervals watch

1. Hi,

I have been given some questions to complete on confidence intervals, but the style of the question just changed and has left me a little confused.

4. The average marathon time for members (sample of 25) of the Men's Nottingham runners club is 4 hours; the standard deviation is 30 minutes. What would the mean be at 1, 2 and 3 standard deviations from the mean?

Is this asking me to work out the confidence intervals of 68%, 95% and 99% respectively? (As we know 68% of observations fall within 1 standard deviation of the mean etc.)

Thanks!
2. Anyone?

Is it simply a misprint and it doesn't mean "the mean or " at all at the end of the question?
3. (Original post by ExWunderkind)
Anyone?
The only way I can reasaonably interpret it, is that it's asking for the confidence intervals of the mean, and left some words out when writing the question.

Even then, it's rather an odd question.
4. (Original post by ghostwalker)
The only way I can reasaonably interpret it, is that it's asking for the confidence intervals of the mean, and left some words out when writing the question.

Even then, it's rather an odd question.
I'm glad you agree.

The next question is worded the exact same way. I'm just going to work out the confidence intervals, and tell my tutor it was all I could work out to do.

Thanks for your help.

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