The first statistics exam had a mean of 74 and a standard deviation of 10 points; the second had a mean of 84 and a standard deviation of 4 points. Anna scored a on both tests. Megan scored 91 on the first exam and 77 on the second. They both totaled 168 points on the two exams, but claims that her total is better. Explain.

The total of Anna's z-scores is. which is greater than Megan's total of. ?

For 300 trading days, the daily closing price of a stock (in $) is well modeled by a Normal model with mean $196.32 and standard deviation $7.19. According to this model, what is the probability that on a randomly selected day in this period the stock price closed as follows.

a) above $210.70?

b) below $203.51?

c) between $181.94 and $210.70?

d) Which would be more unusual, a day on which the stock price closed above $209 or below $180?

what are the percentages?