Look in the back of your statistics textbook for a table called something like “area under normal distribution” to find the proportion/probability ± .10, and use its Z score.
± Z = (score-mean)/(SD/√n)
Calculate for the Z score both positive and negative.
Use the given confidence level and sample data to find a confidence interval for the population standard deviation. Assume that a simple random sample has been selected from a population that has a normal distribution.
Salaries of college professors who took a math course in college
80% confidence; n= 91, x = $66,400, s= $ 19,811
1 answer
1 answer