Standardized measures seem to point to that the average level of anxiety has increased gradually over the past 50 years (Twenge, 2000). In the 1950's the average score on the Child Manifest Anxiety Scale was µ = 15.1. A sample of n = 16 of today's children produces a mean score of M = 23.3 with SS = 240.
a. Based on the sample, make a point estimate of the population mean anxiety score for today's children.
b. Make an 80% confidence interval estimate of today's population mean.