Question

A random sample of 16 students showed an average age of 25 years and a standard deviation of 2 years. The 98% confidence interval for the true average age of students is what?

Answer 1

The standard error of the sampling distribution of means is:

s.e. `=2/sqrt16=1/2` years old

Explanation:

Next, use the Standard Normal table to find the lower and upper limits for a total area under the curve equal to `98%`:

`z=+-2.326` standard deviations

Lastly, the confidence interval will be centered at the mean `barx=25` years old ...

C.I. `=25+-(2.326)(1/2)=[23.837, 26.163]`

hope that helped