Two students are taking a college entrance exam and known to have a normal distribution of scores. Both students receive raw scores of 63 and 93, which correspond to z scores (often called the...

Two students are taking a college entrance exam and known to have a normal distribution of scores. Both students receive raw scores of 63 and 93, which correspond to z scores (often called the standardized scores) of -1 and 1.5 respectively. Answer the followings:

Calculate the value of standard deviation of the raw exam scores.