Question

Studies show that massage therapy has a variety of health benefits and it is not too expensive. A sample of 10 typical one-hour massage therapy sessions showed an average charge of $61. The population standard deviation for a one hour session is s= $5.

a. using 90% confidence, what is the margin of error (to 2 decimals?)

b. using 95% confidence, what is the margin of error (to 2 decimals?)

Answer 1

Given that, sample size (n) = 10, sample mean = $61

and population standard deviation = $5

Here, the population is at least approximately normal is required.

a) A 90% confidence level has significance level of 0.10 and critical value is,

The margin of error (E) is,

=> Margin of error = 2.60

b) A 95% confidence level has significance level of 0.05 and critical value is,

The margin of error (E) is,

=> Margin of error = 3.10