1 Based on a recentstudy, the pH level of the arterial cord(one vessel in the umbilicalcord) is normally distributed with mean 7.21 and standard deviation of 0.11. Find the percentage of preterm infants who have the following arterial cord pH levels.

a. pH levels between 7.00 and 7.50.(Round to two decimal places asneeded.)

b. pH levels over 7.29. (Round to two decimal places asneeded.)

3 A variable of a population has a mean of =73 and a standard deviation of =24.

a. Identify the sampling distribution of the sample mean for samples of size 36.

b. In answering part(a), what assumptions did you make about the distribution of thevariable?

c. Can you answer part(a) if the sample size is 25 instead of 36? Why or whynot?

5 Suppose that the average time spent per day with digital media several years ago was 3 hours and 29 minutes. For lastyear, a random sample of 20 adults in a certain region spent the numbers of hours per day with digital media given in the accompanying table. Preliminary data analyses indicate that thet-interval procedure can reasonably be applied. Find and interpret a 99% confidence interval for lastyear's mean time spent per day with digital media by adults of the region.(Note: x=4.62 hr and s=2.21 hr.)

Interpret the 99% confidence interval. Select all that apply.

A.There is a 99% chance that the mean amount of time spent per day on digital media last year by all adults in the region is between theinterval's bounds.

B. With 99% confidence, the mean amount of time spent per day on digital media last year by all adults in the region is between theinterval's bounds.

C. 99% of all adults in the region spent amounts of time per day on digital media last year that are between theinterval's bounds.

D. 99% of all possible random samples of 20 adults in the region have mean amounts of time spent per day on digital media last year that are between theinterval's bounds.

9 A magazine presented information on top wealth managers in acountry, based on individual clients with accounts of$1 million or more. Data were given for variousvariables, two of which were number of private client managers and private client assets in billions of dollars. Use the technology of your choice and the given data to complete parts(a) through(f). Use the number of client managers as the explanatory variable.

b. Decide whether finding a regression line for the data is reasonable. Choose the correct choice below.

A.There is a linear pattern to thedata, so it is inappropriate to carry out a linear regression.

B.There is a clear curved pattern to thedata, so it is inappropriate to carry out a linear regression.

C.There is a linear pattern to thedata, so it is appropriate to carry out a linear regression.

D.There is a clear curved pattern to thedata, so it is appropriate to carry out a linear regression.

E.There is no clear pattern to thedata, so it is inappropriate to carry out a linear regression.

c. Determine and interpret the regression equation for the data. Select the correct choice belowand, ifnecessary, fill in any answer boxes within your choice.

A.The regression equation is y= +x, which means there is a positive linear relationship between assets and managers.

(Round to three decimal places asneeded.)

B.The regression equation is y= +x, which means there is a negative linear relationship between assets and managers.

(Round to three decimal places asneeded.)

C.This question is not applicable since a regression line is not reasonable.

d. Identify outliers and potential influential observations. Choose the correct answer below.

A.There are no outliers and one influential observation.

B.There is one outlier and no influential observations.

C.There are one or more outliers and influential observations.

D.There are no outliers and no influential observations.

E.This question is not applicable since a regression line is not reasonable.

e. In case a potential outlier ispresent, remove it and discuss the effect. Select the correct choice belowand, ifnecessary, fill in any answer boxes within your choice.

A.The new regressionequation, +x, is about the same as the original.

B.The new regressionequation, +x, is significantly different from the original.

C.There are no potential outliers.

D.This question is not applicable since a regression line is not reasonable.

f. In case a potential influential observation ispresent, remove it and discuss the effect. Select the correct choice belowand, ifnecessary, fill in any answer boxes within your choice.

A.The new regressionequation, +x, is about the same as the original.

B.The new regressionequation, +x, is significantly different from the original.

C.There are no potential influential observations.

D.This question is not applicable since a regression line is not reasonable.

7 Construct astem-and-leaf diagram for the accompanyingdata, using two lines per stem.

21

48

26

21

43

31

41

28

26

26

29

30

41

47

38

42

43

38

44

6 Cadmium, a heavymetal, is toxic to animals.Mushrooms, however, are able to absorb and accumulate cadmium at high concentrations. A government set a safety limit for cadmium in dry vegetables at 0.5 parts per million(ppm). The cadmium levels in a random sample of one species of edible mushroom are in the accompanying data set. At the 10% significancelevel, do the data provide sufficient evidence to conclude that the mean cadmium level in this species of mushroom is greater than thegovernment's recommended limit of 0.5 ppm? Assume that the population standard deviation of cadmium levels in this species of mushroom is 0.42 ppm. Preliminary data analyses indicate that applying thez-test is reasonable.(Note: The sum of the data is 6.94 ppm.)

State the hypotheses for theone-mean z-test.

H0: ( ? )

Ha: ( ? )

-Compute the value of the test statistic.

z= ( ?). (Round to two decimal places asneeded.)

Determine theP-value.

P= ( ? )