How do you calculate the confidence interval?

We are measuring the IQ of students at a college. We choose a sample of 30 students, and find for the same a mean IQ of 118.3, with a standard deviation of 11.4. How do you find the 95% confidence interval for the population mean?

1 Answer
Feb 2, 2017

#mu=barx+-(z*SE)#

Explanation:

Confidence interval of mean

#mu=barx+-(z*SE)#

Where -

#mu - # Population Mean
#barx-# Sample Mean
#z-# Critical Value [depends on confidence level 90% (= 1.64) or 95% (=1.96) or 99% (=2.58)]
#SE-# Standard Error