LetZ

be a standard normal random variable. Use the calculator provided, orthis table, to determine the value ofc

.

=P0.85Zc=0.1727

Carry your intermediate computations to at least four decimal places. Round your answer to two decimal places.

2)Below is a graph of a normal distribution with mean=

5

and standard deviation=

4

. The shaded region represents the probability of obtaining a value from this distribution that is between9

and11

Shade the corresponding region under the standard normal density curve below.

3)

Below is a graph of a normal distribution with mean=

3

and standard deviation=

2

. The shaded region represents the probability of obtaining a value from this distribution that is between

6

and

2

3)

Alcohol withdrawal occurs when a person who uses alcohol excessively suddenly stops the alcohol use. Studies have shown that the onset of withdrawal is experienced a mean of39.5

hours after the last drink, with a standard deviation of18

hours. A sample of38

people who use alcohol excessively is to be taken. What is the probability that the sample mean time between the last drink and the onset of withdrawal will be38.5

hours or less?

Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.

5)A manufacturing process produces semiconductor chips with a known failure rate of6.7

%

. If a random sample of285

chips is selected, approximate the probability that at most18

will be defective. Use the normal approximation to the binomial with a correction for continuity.

Round your answer to at least three decimal places. Do not round any intermediate steps.

(If necessary, consult alist of formulas.)

6)Suppose that15

%

of the people in a large city have used a hospital emergency room in the past year. If a random sample of145

people from the city is taken, approximate the probability that more than18

used an emergency room in the past year. Use the normal approximation to the binomial with a correction for continuity.

Round your answer to at least three decimal places. Do not round any intermediate steps.