# A sample of 16 students is taken

A sample of 16 students is taken. The average age in the sample was 22 years with a standard deviation of 6 years. Construct a 95 % confidence interval for the average age of the population.

**Solution: **Similar to the previous problem, a 95% confidence interval for the mean of the population is given by

_{}

where _{}corresponds to the sample mean, _{}corresponds to the standard deviation, _{}corresponds to the sample size and _{}corresponds to the cutoff point to the standard normal distribution. Since we want 95% confidence interval, we take_{}, and then we look up the normal distribution table to get that_{}. Replacing all this information in the equation we obtain:

_{}

**GO TO NEXT PROBLEM >>**