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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


    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 -

    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.


    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 -

    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
    Comments:





    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
    Comments:





    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
    Comments:





    Question 4. 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
    CORRECT 52
    Instructor Explanation: See section 12.5 of the textbook.




    Points Received: 1 of 1
    Comments:





    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
    Comments:





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




    Student Answer: –0.073
    CORRECT –0.094
    –0.203
    –0.149
    Instructor Explanation: See section 12.8 of the textbook.




    Points Received: 1 of 1
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:





    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
    Comments:

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