Grades on a standardized test are known to have a mean of 500for students in the US. The test is administered to 600 randomlyselected students in Florida. In this subsample, the mean is 508,and the standard deviation is 75
i. Construct a 95% confidence interval for the average testscore for students in Florida.
ii. Is there statistically significant evidence that students inFlorida perform differently from other students in the US?
iii. Another 500 students are selected at random from Florida.They are given a 3 hour preparation course before the test isadministered. Their average test score is 514, with a standarddeviation of 15. Construct a 95% confidence interval. Is therestatistically significant evidence that the preparation coursehelped? What conditions must be met in order for the results tohave a causal interpretation?
