# Math

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Can someone please help me with these three question? I having a very difficlut time answering them

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.

Points Received: 1 of 1

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

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.

Points Received: 1 of 1

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

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

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 0 of 1

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

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.

Points Received: 1 of 1

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

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

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.

Points Received: 1 of 1

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

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

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.

Points Received: 0 of 1

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.

Points Received: 1 of 1

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

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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

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

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

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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

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

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

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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

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

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

• 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.

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

Points Received: 0 of 1

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

Student Answer: INCORRECT 1694
186.67
CORRECT 14.97
224.1
Instructor Explanation: See section 12.4 of the textbook.

Points Received: 0 of 1

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

Student Answer: INCORRECT 0.151
–0.349
0.349
CORRECT 0.849
Instructor Explanation: See section 12.6 of the textbook.

Points Received: 0 of 1

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.

Points Received: 1 of 1

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

Student Answer: 75th percentile
30th percentile
80th percentile
CORRECT 70th percentile
Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

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.

Points Received: 1 of 1

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.

Points Received: 0 of 1

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.

Points Received: 1 of 1

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.

Points Received: 0 of 1

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.

Points Received: 1 of 1

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

Student Answer: INCORRECT 88
CORRECT 89
87
90
Instructor Explanation: See section 12.5 of the textbook.

Points Received: 0 of 1

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.

Points Received: 0 of 1

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.

Points Received: 0 of 1

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.

Student Answer: CORRECT stratified
random
cluster
systematic
Instructor Explanation: See section 12.1 of the textbook.

Points Received: 1 of 1

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.

Points Received: 0 of 1

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?

Student Answer: INCORRECT 379
381
378
CORRECT 380
Instructor Explanation: See section 12.5 of the textbook.

Points Received: 0 of 1

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?

Student Answer: CORRECT Kelly
Fran
Instructor Explanation: See section 12.5 of the textbook.

Points Received: 1 of 1

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

Student Answer: CORRECT 0.908
0.088
0.410
0.498
Instructor Explanation: See section 12.6 of the textbook.

Points Received: 1 of 1

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.

Points Received: 0 of 1

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

Student Answer: INCORRECT 95%
99.7%
CORRECT 68%
65%
Instructor Explanation: See section 12.6 of the textbook.

Points Received: 0 of 1

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