Question

Determine the point estimate. An article in an educational journal discussing a non-conventional high school reading program reports a 95% confidence interval of (520 , 560) for the average score on the reading portion of the SAT. The study was based on a random sample of 20 students and it was assumed that SAT scores would be approximately normally distributed. Determine the sample mean that was used to build this confidence interval.

Answer 1

Explanation:

CI ( 95 % ) means α = 5 % α = 0,05 α /2 = 0,025

If we have a normal distribution and build a CI by symmetry such CI has as a middle point the mean in this case

CI 95 % = ( 520 ; 560 )

the mean is (520 + 560 ) / 2

mean = 540