5.2-5.3

Q1

Assume the random variable x is normally distributed with mean =87 and standard deviation =5. Find the indicated probability.

P(x<77)

Q2

Assume the random variable x is normally distributed with mean =50 and standard deviation =7. Find the indicated probability.

P(x>43)

Q6

Use the normal distribution of SAT critical reading scores for which the mean is 501 and the standard deviation is 114. Assume the variable x is normally distributed.

(a)

What percent of the SAT verbal scores are less than 600?

(b)

If 1000 SAT verbal scores are randomlyselected, about how many would you expect to be greater than 550?

Q7

Use the standard normal table to find thez-score that corresponds to the cumulative area 0.9525. If the area is not in thetable, use the entry closest to the area. If the area is halfway between twoentries, use thez-score halfway between the correspondingz-scores.

P(x>43)=

nothing