Use the normal distribution of SAT critical reading scores for which the mean is 513 and the standard deviation is 111. Assume the variable x is normally distributed.

A) What percent of the SAT verbal scores are less than 625?
B) If 1000 SAT verbal scores are ramdonly selected, about how many would you expect to be greater than 575? Thanks in Advance!

Question

Use the normal distribution of SAT critical reading scores for which the mean is 513 and the standard deviation is 111. Assume the variable x is normally distributed.

 A) What percent of the SAT verbal scores are less than 625?
B) If 1000 SAT verbal scores are ramdonly selected, about how many would you expect to be greater than 575? Thanks in Advance!

directrix · Answer

A) Compute the Z-score for 635 by solving z = (625 - 513) / 111. Then, find that z-score on the table of values of area under the standard normal distribution curve and read out of the table the value of the associated percentage.