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Construct 90%, 95%, and 99% confidence intervals to estimate from the following

ID: 3319474 • Letter: C

Question

Construct 90%, 95%, and 99% confidence intervals to estimate from the following data. State the point estimate. Assume the data come from a normally distributed population.
13.5 11.6 11.9 12.3 12.5 11.4 12.0
11.7 11.8 13.5

(Round the intermediate values to 4 decimal places. Round your answers to 2 decimal places.)
90% confidence interval: 11.83 12.61 (correct)
95% confidence interval: 11.74 12.70 (correct)
99% confidence interval: 11.53 12.91 (incorrect) -- This is the only one I'm having trouble with.
The point estimate is 12.22

Explanation / Answer

The statistical software output for this problem is:

One sample T confidence interval:
: Mean of variable

99% confidence interval results:

Hence,

99% confidence interval will be:

11.45 12.99

Variable Sample Mean Std. Err. DF L. Limit U. Limit Data 12.22 0.23607908 9 11.452782 12.987218