homework

Assignment 08

MA260 Statistical Analysis I

Directions: Be sure to save an electronic copy of your answer before submitting it to Ashworth College for grading. Unless otherwise stated, answer in complete sentences, and be sure to use correct English, spelling, and grammar. Refer to the “Assignment Format” page located on the Course Home page for specific format requirements.

NOTE: Show your work in the problems.

1. A recent article in the Myrtle Beach Sun Times reported that the mean labor cost to repair a color television is $90 with a standard deviation of $22. Monte’s TV Sales and Service completed repairs on two sets this morning. The labor cost for the first was $75 and it was $100 for the second. Compute
z
values for each and comment on your findings.

2. The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds.

a. What is the area between 415 pounds and the mean?

b. What is the area between the mean and 395 pounds?

c. What is the probability of selecting a value at random and discovering that it has a value of less than 395 pounds?

3. The monthly sales of mufflers in the Richmond, VA area follow the normal distribution with a mean of 1200 and a standard deviation of 225. The manufacturer would like to establish inventory levels such that there is only a 5% chance of running out of stock. Where should the manufacturer set the inventory levels?

4. Research on new juvenile delinquents revealed that 38% of them committed another crime.

a. What is the probability that of the last 100 new juvenile delinquents put on probation, 30 or more will commit another crime?

b. What is the probability that 40 or fewer of the delinquents will commit another crime?

c. What is the probability that between 30 and 40 of the delinquents will commit another crime?

5. An Air Force study indicates that the probability of a disaster such as the January 28, 1986 explosion of the space shuttle Challenger was 1 in 35. The Challenger flight was the 25th mission.

a. How many disasters would you expect in the first 25 flights?

b. Use the normal approximation to estimate the probability of at least one disaster in 25 missions.

Grading Rubric

Please refer to the rubric below for the grading criteria for this assignment.

CATEGORYExemplarySatisfactoryUnsatisfactoryUnacceptable

15 points11 points7 points3 points

The student

sets up both

equations correctly and

provides the correct

answer

for each.

The student sets up

both
equations correctly and

provides the correct answer

for only one

question.

The student sets up both
equations correctly and
provides the correct answer

for neither question.

The student sets up only

one

equation correctly and

provides the correct

answer for only one

question.
15 points11 points7 points3 points

The student sets up all

equations correctly and

provides 3 correct

answers.

The student sets up 3

equations correctly and

provides 2 or less correct

answers.

The student sets up 2

questions correctly and

provides 1 or less correct

answers.

The student sets up 1

question correctly and

provides 1 or less correct
answers.

15 points11 points7 points0 points

The student sets up the

equation correctly and

provides the correct

answer.

The student sets up the

equation correctly and does

not provide the correct

answer.

The student does not

set up

the equation correctly and

does not provide the

correct answer.

The student does not

provide the equation or

the answer.

15 points11 points7 points3 points
The student sets up all
equations correctly and

provides 3 correct answers.

The student sets up 3
equations correctly and
provides 2 or less correct
answers.
The student sets up 2
questions correctly and
provides 1 or less correct
answers.
The student sets up 1
question correctly and
provides 1 or less correct
answers.
15 points11 points7 points3 points
The student sets up both
equations correctly and
provides the correct answer
for each.
The student sets up both
equations correctly and
provides the correct answer

for only one question.

The student sets up both
equations correctly and
provides the correct answer
for neither question.
The student sets up only

one equation correctly and

provides the correct
answer for only one
question.

10 points 8 points 5 points 2 points

Student does not make any

errors in grammar or spelling,

especially those that distract

the reader from the

content.

Student makes 1-2 errors in

grammar or spelling that

distract the reader from the

content.

Student makes 3-4 errors in

grammar or spelling that
distract the reader from the
content.

Student makes more than

4 errors in grammar or

spelling that distract the

reader from the content.

15 points 12 points 8 points 5 points

The paper is written in

proper APA and

organizational format. All

sources used for quotes

and

facts are credible and cited

correctly. Excellent

organization, including a

variety of thoughtful

transitions.

The paper is written in

proper format with only 1-2

errors. All sources used for

quotes and facts are

credible, and most are cited

correctly. Adequate

organization includes a

variety of appropriate

transitions.
The paper is written in

proper format with only 3-5

errors. Most sources used

for quotes and facts are

credible and cited correctly.

Essay is poorly organized,

but may include a few

effective transitions.

The paper is not written in

proper format. Many

sources used for quotes

and facts are less than

credible (suspect) and/or

are not cited correctly.

Essay is disorganized and

does not include effective

transitions.
The student

includes the

equations and

solves Parts a, b,

and c for #4.

The student
includes the
equations and

answers for Parts a

and b for #5.

Format – APA

Format, Citations,

Organization,

Transitions (15

Points)

The student sets up

the equations for #1

and solves them.

Mechanics (10

Points)

The student solves

Parts a, b, and c for

#2.

The student shows

the equation and

the answer for #3.