Complete "Practice Exercise 1" (page 157) and "Practice Exercise 11" (page 180) in the textbook. For the data set listed, use Excel to extract the mean and standard deviation for the sample of lengths of stay for cardiac patients. Use the following Excel steps:

1) Enter the data set into Excel.

2) Click on the Data tab at the top.

3) Highlight your data set with your mouse.

4) Click on the Data Analysis tab at the top right.

5) Click on Descriptive Statistics in the analysis tool list.

6) Find the mean and standard deviation of the data sets.

7) Send the results to instructor via e-mail, along with your analysis of the description of the data set.

APA format is not required, but solid academic writing is expected.

This assignment uses a grading rubric. Instructors will be using the rubric to grade the assignment; therefore, students should review the rubric prior to beginning the assignment to become familiar with the assignment criteria and expectations for successful completion of the assignment.

Exercises

156 Chapter 6: Inferences Concerning the MeanR,O

1. To estimate the time required to

provide a given laboratory procedure,

suppose that we measured

the amount of time required

when the service was provided

on 60 occasions. Based on this

sample, we obtained a mean of

20.32 minutes and a standard deviation

of 3.82 minutes.What

can we say with a probability of

0.95 about the size of the error

when we use 20.32 minutes as an

estimate of the true average time

required to provide the procedure?

(Hint:

X _ _ _ Z_/2

[S/√_n])

2. Use the data in Exercise 1 to construct

a 98% confidence interval.

11. Suppose that the medical staff indicates

that the results of a given

laboratory procedure must be

available 30 minutes after the

physician submits a request for

the service. In this situation, if

the results arrived 30 minutes or

less after the request, we regard

the performance of the laboratory

as timely. If results arrived

more than 30 minutes after the

request, we regard the performance

as tardy. Focusing on the

day, evening, and night shifts,

suppose that we selected a random

sample and obtained the

following results:

Shift

Performance Day Evening Night

Timely 100 80 40

Tardy 20 30 40

If _ _ 0.05, use these results to

test the proposition that the performance

of the laboratory is independent

of shift.