Answer:
95% confidence interval for the population variance = [56.31 , 224.75].
Step-by-step explanation:
We are given that Scores on an IQ test are normally distributed. A sample of 18 IQ scores had standard deviation s = 10.
The pivotal quantity for 95% confidence interval for the population variance is given by;
~
95% confidence interval for the population variance is;
P(7.564 < < 30.19) = 0.95
P(7.564 < < 30.19) = 0.95
P( < < ) = 0.95
P( < < ) = 0.95
95% Confidence interval for = [ , ]
= [ , ]
= [ 56.31 , 224.75 ]
Therefore, 95% confidence interval for the population variance, is [ 56.31 , 224.75 ] .