Standardized measures seem to indicate that the average 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 μ= 15.1. A sample of n = 16 of today's children produces a mean score of M = 23.3 with SS = 240. Based on the sample, has there been a significant increase in the average level of anxiety since the 1950s? Use a one-tail test with α= .05.
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
Standardized measures seem to indicate that the average 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 μ= 15.1. A sample of n = 16 of today's children produces a mean score of M = 23.3 with SS = 240.
Based on the sample, has there been a significant increase in the average level of anxiety since the 1950s? Use a one-tail test with α= .05.
Please answer the question using all of the steps presented on your practice problem assignment. (null in word, alternative in words, null in symbols, alternative in symbols, critical region t, df, all steps in the analysis computing your computed t, make a decision, and give a conclusion.
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