A simple random sample of 20 third-grade children from a certain school district is selected,and each is given a test to measure his/her reading ability.You are interested in calculating a 95% confidence interval for the population mean score.In the sample,the mean score is 64 points and the standard deviation is 12 points.What is the margin of error associated with the confidence interval?
A)2.68 points
B)4.64 points
C)5.62 points
D)6.84 points

Question

Quizplus · Accepted Answer

The margin of error is calculated using the formula: $ ME = t^* \times \frac{s}{\sqrt{n}} $, where $ t^* $ is the t-score for a 95% confidence level with 19 degrees of freedom (approximately 2.093), $ s $ is the standard deviation (12), and $ n $ is the sample size (20). Calculating gives $ ME = 2.093 \times \frac{12}{\sqrt{20}} \approx 5.62 $.

A Simple Random Sample of 20 Third-Grade Children from a Certain