Question

A random sample of 10 observations has been drawn from a normal population, and the sample variance is found to be s² = 19.5. Determine the 98% confidence interval for ó².

Answer 1

Find the 98% confidence interval using a z-table. Find the formula for the confidence interval using standard deviation. Remember that standard deviation is the square root of the variance. Substitute what you know into the formula from the information given to determine the confidence interval.

Answer 2

you are constructing a 95% confidence interval using the information: n = 50, xbar = 54.3, s = 2.1 and E = 0.65. What is the value of the middle of the interval?