Question: Scores on a standardized achievement test are normally distributed. If all the children of selected grades in a school are tested, determine the 95% confidence intervals for the means for the grades tested.

(a) Grade 3: Mean = 70, standard error = 9

(b) Grade 5: Mean = 100, standard error = 10

(c) Grade 7: Mean = 130, standard error = 12

(d) Grade 9: Mean = 150, standard error = 15