# t critical, confidence interval

See the attached file.

2) Use Table 4 of the appendix to find tc for a 0.99 confidence level when the sample size is 4.

4) Use Table 4 of the Appendix to find tc for 0.95 confidence level when the sample size is 12.

6) Wildlife: Wolf Pups. The number of pups in the wolf dens of the southwestern United States is recorded below for 16 wolf dens.

5, 8, 7, 5, 3, 4, 3, 9

5 8 5 6 5 6 4 7

a) use a calculator with mean and standard deviation keys to verify that the sample mean is x with line over top =5.63 pups with sample standard deviation s = 1.78 pups.

B) Compute an 85% confidence interval for the population mean number of wolf pups per den in the southwestern United States.

10) Hospital: Charity Care. What percentage of hospitals provides at least some charity care? The following problem is based on information taken from State Health Care Data: Utilization, Spending, and Characteristics. Based on a random sample of hospital reports from eastern states, the following information was obtained, (units in percentage of hospitals providing at least some charity care):

57.1 56.2 53.0 66.1 59.0 64.7 70.1 64.7 53.5 78.2

Use a calculator with mean and sample standard deviation keys to verify that x (with line over x) = 62.3% and s = 8.0%. Find a 90% confidence interval for the population average µ of the percentage of hospitals providing at least some charity care.

Please see the attached file.

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#### Solution Preview

Please see attached files (either) for answers.

2) Use Table 4 of the appendix to find tc for a 0.99 confidence level when the sample size is 4.

Confidence level= 0.99

Or Significance level α= 0.01

n= 4

degrees of freedom=n-1= 3 =4- 1

No of tails= 2

t value= 5.8409 (corresponding to 3 degrees of freedom and 0.01 significance level )

Answer: 5.8409

4) Use Table 4 of the Appendix to find tc for 0.95 confidence level when the sample size is 12.

Confidence level= 0.95

Or Significance level α= 0.05

n= 12

degrees of freedom=n-1= 11 =12- 1

No of tails= 2

t value= 2.2010 (corresponding to 11 degrees of freedom and 0.05 significance level )

Answer: 2.2010

6) Wildlife: Wolf Pups. The number of pups in the wolf dens of the southwestern United States is recorded below for 16 wolf dens.

5, 8, 7, 5, 3, 4, 3, 9

5 8 5 6 5 6 4 7

a) use a calculator with mean and standard deviation keys to verify that the ...

#### Solution Summary

The solution calculates t critical and confidence interval.