# Math

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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 - ,

automatically 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

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?

Fran
Instructor Explanation: See section 12.5 of the textbook.

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.

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

89
87
90
Instructor Explanation: See section 12.5 of the textbook.

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

Nonlinear relationship
Positive linear relationship
Negative linear relationship
Instructor Explanation: See section 12.8 of the textbook.

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.

0.332 = 33.2%
0.168 = 16.8%
0.345 = 34.5%
Instructor Explanation: See section 12.6 of the textbook.

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

–0.499
0.999
0.001
Instructor Explanation: See section 12.6 of the textbook.

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

–0.349
0.349
0.849
Instructor Explanation: See section 12.6 of the textbook.

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?

Sanjo
Instructor Explanation: See section 12.5 of the textbook.

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.

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

0.088
0.410
0.498
Instructor Explanation: See section 12.6 of the textbook.

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.

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.

13. Question : Find the standard deviation.
44 46 33 10 50 27

186.67
14.97
224.1
Instructor Explanation: See section 12.4 of the textbook.

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.

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.

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.

random
cluster
systematic
Instructor Explanation: See section 12.1 of the textbook.

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

99.7%
68%
65%
Instructor Explanation: See section 12.6 of the textbook.

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.

19. Question : Find the median.
2 27 38 55 49 9 53 34

36
49
52
Instructor Explanation: See section 12.3 of the textbook.

• Math - ,

these answers are incorrect, i chnaged my answers to reflect his and all the answers that he has were incorrect don't use this the person chnaged the score

• Math - ,

1. Question : Find the area under the normal distribution curve between z = 1.52 and z = 2.43.

0.436
0.493
0.057
Instructor Explanation: See section 12.6 of the textbook.

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

99.7%
68%
65%
Instructor Explanation: See section 12.6 of the textbook.

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.

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.

0.820 = 82.0%
0.156 = 15.6%
0.943 = 94.3%
Instructor Explanation: See section 12.6 of the textbook.

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.

6. Question : Find the standard deviation.
44 46 33 10 50 27

186.67
14.97
224.1
Instructor Explanation: See section 12.4 of the textbook.

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?

Fran
Instructor Explanation: See section 12.5 of the textbook.

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.

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

Nonlinear relationship
Positive linear relationship
Negative linear relationship
Instructor Explanation: See section 12.8 of the textbook.

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

30th percentile
80th percentile
70th percentile
Instructor Explanation: See section 12.5 of the textbook.

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

0.088
0.410
0.498
Instructor Explanation: See section 12.6 of the textbook.

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

44
48
52
Instructor Explanation: See section 12.5 of the textbook.

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.

random
cluster
systematic
Instructor Explanation: See section 12.1 of the textbook.

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?

381
378
380
Instructor Explanation: See section 12.5 of the textbook.

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?

Sanjo
Instructor Explanation: See section 12.5 of the textbook.

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

–0.499
0.999
0.001
Instructor Explanation: See section 12.6 of the textbook.

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

–0.349
0.349
0.849
Instructor Explanation: See section 12.6 of the textbook.

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.

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.

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.

• Math - ,

For 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).

• Math - ,

SO MUCH FOR THE HELP. IF YOU ARE GOING TO POST HERE MAE SURE YOUR ANSWERS ARE LEGIT ....NOT COOL ;/

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

–0.499
CORRECT 0.999
0.001
Instructor Explanation: See section 12.6 of the textbook.

Question 2. Question :
Find the standard deviation.
44 46 33 10 50 27

186.67
CORRECT 14.97
224.1
Instructor Explanation: See section 12.4 of the textbook.

Question 3. Question :
Find the area under the normal distribution curve to the right of z = –1.03.

–0.349
0.349
CORRECT 0.849
Instructor Explanation: See section 12.6 of the textbook.

Question 4. Question :
If a student's percentile rank in a class of 400 students is 87, find the student's class rank.

44
48
CORRECT 52
Instructor Explanation: See section 12.5 of the textbook.

Question 5. 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

30th percentile
80th percentile
CORRECT 70th percentile
Instructor Explanation: See section 12.5 of the textbook.

Question 6. Question :
Find the value for the correlation coefficient r.

CORRECT –0.094
–0.203
–0.149
Instructor Explanation: See section 12.8 of the textbook.

Question 7. Question :
Which of the following is not a property of a normal distribution?

Student Answer: INCORRECT It never touches the x-axis.
It is continuous.
The mean, median, and mode are equal.
CORRECT It is bimodal (i.e., it has two modes).
Instructor Explanation: See section 12.6 of the textbook.

Question 8. Question :
Which statement is true for a statistical study?

Student Answer: CORRECT 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.

Question 9. 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: INCORRECT r is significant at 5% and at 1%.
r is significant at 5%, but not at 1%.
CORRECT r is is not significant at 5% or at 1%.
Instructor Explanation: See section 12.8 of the textbook.

Question 10. Question :
Find the equation of the regression line.

Student Answer: CORRECT 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.

Question 11. Question :
If a student's rank in a class of 400 students is 44, find the student's percentile rank.

CORRECT 89
87
90
Instructor Explanation: See section 12.5 of the textbook.

Question 12. Question :
Use a scatter plot to deternine the relationship between the x values and the y values.

Student Answer: CORRECT Negative linear relationship
Nonlinear relationship
INCORRECT No relationship
Positive linear relationship
Instructor Explanation: See section 12.8 of the textbook.

Question 13. Question :
Determine whether a correlation coefficient of r = –0.405 is significant at the 5% level for a sample size of 22.

Student Answer: CORRECT r is not significant at 5%.
INCORRECT r is significant at 5%.
Instructor Explanation: See section 12.8 of the textbook.

Question 14. 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.

random
cluster
systematic
Instructor Explanation: See section 12.1 of the textbook.

Question 15. 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: INCORRECT mean = 37.3; median = 3.25
mean = 3.73; median = 3.4
mean =37.3; median = 3.4
CORRECT mean = 3.73; median = 3.25
Instructor Explanation: See section 12.3 of the textbook.

Question 16. Question :
Kate scored in the 95th percentile rank on an exam. If 400 students took the exam, how many students scored lower than Kate?

381
378
CORRECT 380
Instructor Explanation: See section 12.5 of the textbook.

Question 17. 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?

Fran
Instructor Explanation: See section 12.5 of the textbook.

Question 18. Question :
Find the area under the normal distribution curve between z = –1.34 and z = 2.95.

0.088
0.410
0.498
Instructor Explanation: See section 12.6 of the textbook.

Question 19. 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: INCORRECT 0.144 = 14.4%
CORRECT 0.820 = 82.0%
0.156 = 15.6%
0.943 = 94.3%
Instructor Explanation: See section 12.6 of the textbook.

Question 20. Question :
The area under a normal distribution curve that lies within one standard deviation of the mean is approximately _____.

99.7%
CORRECT 68%
65%
Instructor Explanation: See section 12.6 of the textbook.