Daily water consumption for an Ohio city of

Daily water consumption for an Ohio city of 50,000 residents is normally distributed with a mean of 1250 and a standard deviation of 85, both measured in thousands of gallons per day.

The municipal water company's civil engineer would like to know what proportion of days water consumption will exceed 1375 thousands of gallons.

What is the Z value associated with 1375 thousands of gallons per day?

Z =

Question 1 options:

1..37

16.18

1.47

None of the above.

SaveQuestion 2 (2 points)

Refer to the previous question.

Using the z value calculated in the previous question, calculate the proportion of days that water consumption will exceed 1375 thousands of gallons?

P(X > 1375) = P(Z > _______) =

Question 2 options:

0.4292

0.0708

0.0853

0.4147

SaveQuestion 3 (2 points)

Refer to the previous question.

The municipal water company wants to have sufficient capacity so that its ability to deliver water will be inadequate on, at most, 10% of days and needs to determine what water delivery capacity it would need to establish. That is, it needs to determine what water usage amount in thousands of gallons per day (value of X) is at the 90th percentile.

What is the Z-value associated with daily water usage at the 90th percentile?

P(Z > Zo ) = 0.10; Zo =

Question 3 options:

1.282

1.645

1.96

2.576

SaveQuestion 4 (2 points)

Refer to the previous question.

Using the Z value from the previous question calculate a value of daily water usage in thousands of gallons per day (value of X) that is at the 90th percentile.

P( X > Xo) = 0.10; Xo =

Question 4 options:

1250

1359

1185

1335

SaveQuestion 5 (3 points)

Refer to the previous water usage question.

Suppose that a sample of 81 days are selected randomly and water consumption on those days examined.

What is the Z-value associated with the probability that the mean water consumption of the 81 days will exceed 1270 thousands of gallons per day?

P(Mean of sample,X bar, the sample mean > 1270) = P( Z > ____________ )

Question 5 options:

0.24

0.48

20

2.12

SaveQuestion 6 (2 points)

Refer to the previous water usage question.

Suppose that a sample of 81 days are selected randomly and water consumption on those days examined.

What is the probability that the mean water consumption of the 81 days will exceed 1270 thousands of gallons per day?

P(Mean of sample,X bar, the sample mean > 1270) =

Question 6 options:

.0.4092

0.0948

0.4830

0.0170

SaveQuestion 7 (3 points)

According to Quality Progress, Feb. 2005, 78% of Bank of America customers expressed some level of satisfaction with B of A services.

What is the Z-value associated with the probability that a simple random sample of 250 customers will have an 82% or better satisfaction rate?

P ( Sample proportion, p-hat, the sample proportion ? 0.82 ) = P ( Z ? _______________ )

Question 7 options:

1.65

1.53

0.04

None of the above.

SaveQuestion 8 (2 points)

Refer to the previous problem above.

According to Quality Progress, Feb. 2005, 78% of Bank of America customers expressed some level of satisfaction with B of A services.

Using the Z value computed in the previous problem, report the probability that the random sample of 250 customers will have an 82% or better satisfaction rate.

P ( Sample proportion, p-hat, the sample proportion ? 0.82 ) =

Question 8 options:

.0630

0.9370

0.3461

0.0539

SaveQuestion 9 (2 points)

Compute the following:

P ( Z ? 2.326 ) =

Question 9 options:

0.01

0.99

0.05

0.45

SaveQuestion 10 (2 points)

Compute the following:

P ( 0 ? Z ? 0.86 ) =

Question 10 options:

0.1217

0.6217

0.8051

0.3051