Thursday

July 24, 2014

July 24, 2014

Posted by **Latisha** on Saturday, February 26, 2011 at 9:02pm.

May first question

To select a _________ sample, the population is divided into disjoint subgroups according to some characteristics like income level, and then a few individuals are selected randomly from each of the subgroups to be in the sample. (Points : 1)

(May choices are)

stratified

random

cluster

systematic

May second question

If a student's percentile rank in a class of 400 students is 87, find the student's class rank. (Points : 1)

(My choices are)

40

44

48

52

My final question

Armia's percentile rank on an exam in a class of 300 is 85. Sanjo's class rank is 42. Who is ranked higher?

(My choices are)

Armia

Sanjo

Thanks you

- Math -
**Anonymous**, Thursday, March 3, 2011 at 6:21pmautomatically computed results of your exam. Grades for essay questions, and comments from your instructor, are in the "Details" section below. Date Taken: 3/3/2011

Time Spent: 1 h , 01 min , 31 secs

Points Received: 16 / 20 (80%)

Question Type: # Of Questions: # Correct:

Multiple Choice 20 16

Grade Details

1. Question : Fran's percentile rank on an exam in a class of 500 is 85. Kelly's class rank is 60. Who is ranked higher?

Student Answer: Kelly

Fran

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

2. Question : Which of the following is not a property of a normal distribution?

Student Answer: It never touches the x-axis.

It is continuous.

The mean, median, and mode are equal.

It is bimodal (i.e., it has two modes).

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

3. Question : If a student's rank in a class of 400 students is 44, find the student's percentile rank.

Student Answer: 88

89

87

90

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

4. Question : Use a scatter plot to deternine the relationship between the x values and the y values.

Student Answer: No relationship

Nonlinear relationship

Positive linear relationship

Negative linear relationship

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 1 of 1

Comments:

5. Question : The average hourly wage of employees of a certain company is $9.83. Assume the variable is normally distributed. If the standard deviation is $4.58, find the probability that a randomly selected employee earns less than $5.43.

Student Answer: 0.313 = 31.3%

0.332 = 33.2%

0.168 = 16.8%

0.345 = 34.5%

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 0 of 1

Comments:

6. Question : Find the area under the normal distribution curve to the right of z = –3.24.

Student Answer: 0.499

–0.499

0.999

0.001

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

7. Question : Find the area under the normal distribution curve to the right of z = –1.03.

Student Answer: 0.151

–0.349

0.349

0.849

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

8. Question : Armia's percentile rank on an exam in a class of 300 is 85. Sanjo's class rank is 42. Who is ranked higher?

Student Answer: Armia

Sanjo

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 0 of 1

Comments:

9. Question : Find the equation of the regression line.

Student Answer: y = 1.7 + 1.9x

y = 2.5 + 2.7x

y = 1.9 + 1.7x

y = 2.7 + 2.5x

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 1 of 1

Comments:

10. Question : Find the area under the normal distribution curve between z = –1.34 and z = 2.95.

Student Answer: 0.908

0.088

0.410

0.498

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

11. Question : Which statement is true for a statistical study?

Student Answer: The sample is a subset of the population.

The population is a subset of the sample.

Instructor Explanation: See section 12.1 of the textbook.

Points Received: 1 of 1

Comments:

12. Question : Find Q1, Q2, and Q3 for the data set below.

5.4 2.0 6.8 3.1 2.9 4.7 2.1 5.0 1.9 3.4

Student Answer: Q1 = 2.05, Q2 = 3.1, Q3 = 5.2

Q1 = 2.05, Q2 = 3.25, Q3 = 5.2

Q1 = 2.1, Q2 = 3.25, Q3 = 5.0

Q1 = 2.1, Q2 = 3.4, Q3 = 5.0

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

13. Question : Find the standard deviation.

44 46 33 10 50 27

Student Answer: 1694

186.67

14.97

224.1

Instructor Explanation: See section 12.4 of the textbook.

Points Received: 1 of 1

Comments:

14. Question : Find the median and the mean for the data set below.

5.4 2.0 6.8 3.1 2.9 4.7 2.1 5.0 1.9 3.4

Student Answer: mean = 37.3; median = 3.25

mean = 3.73; median = 3.4

mean =37.3; median = 3.4

mean = 3.73; median = 3.25

Instructor Explanation: See section 12.3 of the textbook.

Points Received: 0 of 1

Comments:

15. Question : Determine whether a correlation coefficient of r = –0.405 is significant at the 5% level for a sample size of 22.

Student Answer: r is not significant at 5%.

r is significant at 5%.

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 1 of 1

Comments:

16. Question : To select a _________ sample, the population is divided into disjoint subgroups according to some characteristics like income level, and then a few individuals are selected randomly from each of the subgroups to be in the sample.

Student Answer: stratified

random

cluster

systematic

Instructor Explanation: See section 12.1 of the textbook.

Points Received: 0 of 1

Comments:

17. Question : The area under a normal distribution curve that lies within one standard deviation of the mean is approximately _____.

Student Answer: 95%

99.7%

68%

65%

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

18. Question : A data set of size 19 has correlation coefficient of r = –0.432. Test the significance of r at the 5% level and at the 1% level.

Student Answer: r is significant at 5% and at 1%.

r is significant at 5%, but not at 1%.

r is is not significant at 5% or at 1%.

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 1 of 1

Comments:

19. Question : Find the median.

2 27 38 55 49 9 53 34

Student Answer: 38

36

49

52

Instructor Explanation: See section 12.3 of the textbook.

- Math -
**heather**, Sunday, June 26, 2011 at 9:19amthese answers are incorrect, i chnaged my answers to reflect his and all the answers that he has were incorrect dont use this the person chnaged the score

- Math -
**JESSICA**, Sunday, February 19, 2012 at 7:43pm1. Question : Find the area under the normal distribution curve between z = 1.52 and z = 2.43.

Student Answer: 0.929

0.436

0.493

0.057

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

2. Question : The area under a normal distribution curve that lies within one standard deviation of the mean is approximately _____.

Student Answer: 95%

99.7%

68%

65%

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

3. Question : A data set of size 19 has correlation coefficient of r = –0.432. Test the significance of r at the 5% level and at the 1% level.

Student Answer: r is significant at 5% and at 1%.

r is significant at 5%, but not at 1%.

r is is not significant at 5% or at 1%.

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 1 of 1

Comments:

4. Question : The average amount customers at a certain grocery store spend yearly is $636.55. Assume the variable is normally distributed. If the standard deviation is $89.46, find the probability that a randomly selected customer spends between $550.67 and $836.94.

Student Answer: 0.144 = 14.4%

0.820 = 82.0%

0.156 = 15.6%

0.943 = 94.3%

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

5. Question : Find the equation of the regression line.

Student Answer: y = 1.7 + 1.9x

y = 2.5 + 2.7x

y = 1.9 + 1.7x

y = 2.7 + 2.5x

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 0 of 1

Comments:

6. Question : Find the standard deviation.

44 46 33 10 50 27

Student Answer: 1694

186.67

14.97

224.1

Instructor Explanation: See section 12.4 of the textbook.

Points Received: 1 of 1

Comments:

7. Question : Fran's percentile rank on an exam in a class of 500 is 85. Kelly's class rank is 60. Who is ranked higher?

Student Answer: Kelly

Fran

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

8. Question : Determine whether a correlation coefficient of r = –0.405 is significant at the 5% level for a sample size of 22.

Student Answer: r is not significant at 5%.

r is significant at 5%.

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 0 of 1

Comments:

9. Question : Use a scatter plot to deternine the relationship between the x values and the y values.

Student Answer: No relationship

Nonlinear relationship

Positive linear relationship

Negative linear relationship

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 0 of 1

Comments:

10. Question : For the 20 test scores shown, find the percentile rank for a score of 86.

75 63 92 74 86 50 77 82 98 65 71 89 75 66 87 59 70 83 91 73

Student Answer: 75th percentile

30th percentile

80th percentile

70th percentile

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

11. Question : Find the area under the normal distribution curve between z = –1.34 and z = 2.95.

Student Answer: 0.908

0.088

0.410

0.498

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

12. Question : If a student's percentile rank in a class of 400 students is 87, find the student's class rank.

Student Answer: 40

44

48

52

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

13. Question : To select a _________ sample, the population is divided into disjoint subgroups according to some characteristics like income level, and then a few individuals are selected randomly from each of the subgroups to be in the sample.

Student Answer: stratified

random

cluster

systematic

Instructor Explanation: See section 12.1 of the textbook.

Points Received: 1 of 1

Comments:

14. Question : Kate scored in the 95th percentile rank on an exam. If 400 students took the exam, how many students scored lower than Kate?

Student Answer: 379

381

378

380

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

15. Question : Armia's percentile rank on an exam in a class of 300 is 85. Sanjo's class rank is 42. Who is ranked higher?

Student Answer: Armia

Sanjo

Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

Comments:

16. Question : Find the area under the normal distribution curve to the right of z = –3.24.

Student Answer: 0.499

–0.499

0.999

0.001

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

17. Question : Find the area under the normal distribution curve to the right of z = –1.03.

Student Answer: 0.151

–0.349

0.349

0.849

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

18. Question : Find the median and the mean for the data set below.

5.4 2.0 6.8 3.1 2.9 4.7 2.1 5.0 1.9 3.4

Student Answer: mean = 37.3; median = 3.25

mean = 3.73; median = 3.4

mean =37.3; median = 3.4

mean = 3.73; median = 3.25

Instructor Explanation: See section 12.3 of the textbook.

Points Received: 1 of 1

Comments:

19. Question : Which statement is true for a statistical study?

Student Answer: The sample is a subset of the population.

The population is a subset of the sample.

Instructor Explanation: See section 12.1 of the textbook.

Points Received: 1 of 1

Comments:

20. Question : Which of the following is not a property of a normal distribution?

Student Answer: It never touches the x-axis.

It is continuous.

The mean, median, and mode are equal.

It is bimodal (i.e., it has two modes).

Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

Comments:

- Math -
**JESSICA**, Sunday, February 19, 2012 at 7:56pmFor some reason when posted the answers show differently. Here are all the answers, which are correct:

1.0.057

2. 68%

3.r is not significant at 5% or at 1%.

4.0.820 = 82.0%

5.y = 1.7 + 1.9x

6.14.97

7.Kelly

8.r is not significant at 5%.

9.Positive linear relationship

10.70th percentile

11.0.908

12.52

13.stratified

14.380

15.Sanjo

16.0.999

17.0.849

18.mean = 3.73; median = 3.25

19.The sample is a subset of the population.

20.It is bimodal (i.e., it has two modes).

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