A medical researcher measured the body temperature of 400 healthy adults. Body temperature is approximately normal with a standard deviation = 0.5 degrees Fahrenheit. The sample mean temperature was 98.4 degrees. Construct a 95% confidence interval for the true mean body temperature. Using the confidence interval, is there any evidence to suggest that the average temperature of healthy adults is different from 98.6 degrees F?

I'm particularly interested in the conclusion and the reasoning WHY there IS or ISN'T evidence to suggest that the average temperature of healthy adults is different from 98.6 degrees?

Thank you.