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September 20, 2014

September 20, 2014

Posted by **Anonymous** on Monday, July 16, 2012 at 12:00am.

Time Spent: h , min , 19 secs

Points Received: 18 / 20 (90%)

Question Type: # Of Questions: # Correct:

Multiple Choice 20 18

Grade Details - All Questions

1. 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:

2. 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: 0 of 1

Comments: correct answer is 0.849

3. 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:

4. 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:

5. 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:

6. 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:

7. 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:

8. 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:

9. 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: Correct answer is 16.8

10. 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:

11. 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:

12. 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:

13. 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:

14. 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.

Points Received: 1 of 1

Comments:

15. 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:

16. 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:

17. 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:

18. Question : Find the value for the correlation coefficient r.

Student Answer: –0.073

–0.094

–0.203

–0.149

Instructor Explanation: See section 12.8 of the textbook.

Points Received: 1 of 1

Comments:

19. 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:

20. 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:

- Math 126 -
**Christine**, Saturday, December 1, 2012 at 4:06pmThe answer is 52

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