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Confidence Interval Interpretation


New member
Feb 4, 2012
This is basic statistics, but my prof doesn't teach in a way that's easy for me to understand

"Tire wear is often measured by the number of km until wearout. Below are the "distances until wearout" of a random sample of 15 radial tires of a particular brand. Assume the sample comes from a normal distribution.

a) EStimate the mean number of kilometres until wearout fo this brand of tire using a 95% confidence interval. Interpret the interval.

I've found the mean - it's 56. I'm just confused as to how I'm supposed to "interpret" the interval - help would be greatly appreciated, and let me know if you need the list of tire data!

Thanks so very much!


Staff member
Apr 12, 2005
"56" is not an interval. You will need the variance to create the confidence interval. THEN you can intrepret the result.