## Question 391:

Asked on September 18, 2008

Tags:
Confidence Intervals ,
t-statistic ,
Critical Value ,
Standard Error of the Mean

1

## Answer:

No answer provided yet.

- The mean is 32.08
- Standard deviation is .6730
- The Standard Error of the Mean (SEM) is sd/SQRT(n) = .6730/3.162 = .2128
- The critical value from the t-distribution for a 95% CI can be found using Excel =TINV(0.05,9) = 2.262
- The margin of error is the critical value * them SEM = 2.262*.2128 =.4813
- The 95% CI is the mean minus and plus the margin of error = 32.08 +/- .4813
- The 95% Confidence Interval is then (31.95, 32.56)