An SRS of 20 recent birth records at the local hospital were selected.In the sample, the average birth weight was 121.4 ounces and the standard deviation was 7.5 ounces. Assume that in the population of all babies born in this hospital, the birth weights follow a Normal distribution, with some mean

.

Reference: Ref 16-1

The standard error of the sample mean is

Select one:

a.

0.4.

b.

27.1.

c.

7.5.

d

1.7.

To estimate, the mean salary of full professors at American colleges and universities, you obtain the salaries of a random sample of 400 full professors. The sample mean is= $73,220, and the sample standard deviation iss= $4400.

A 99% confidence interval foris

Select one:

a.

73,220 572.

b.

73,220 431.

c.

73,220 28.6.

d.

73,220 11,440.

An SRS of 20 recent birth records at the local hospital were selected.In the sample, the average birth weight was 121.4 ounces and the standard deviation was 7.5 ounces. Assume that in the population of all babies born in this hospital, the birth weights follow a Normal distribution, with some mean

.

Reference: Ref 16-1

A 90% confidence interval for the population mean birth weight based on these data is

Select one:

a.

121.4 2.89 ounces.

b.

121.4 5.63 ounces.

c.

121.4 3.29 ounces.

d.

121.4 4.80 ounces.