Standardized measures seem to indicate that the aver-age level of anxiety has increased gradually over the past 50 years (Twenge, 2000). In the 1950s, the average score on the Child Manifest Anxiety Scale was = 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, has there been a significant change in the average level of anxiety since the 1950s? Use a two-tailed test with = .01. b. Make a 90% confidence interval estimate of today's population mean level of anxiety. c. Write a sentence that demonstrates how the outcome of the hypothesis test and the confidence interval would appear in a research report.

Please provide steps