## MAT 126 Week 5 Quiz

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

2. 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

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

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

5. Question : Find the median.

2 27 38 55 49 9 53 34

6. 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

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

8. 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.

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

10. 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.

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

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

13. 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?

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

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

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

17. 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?

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

19. Question : Find the standard deviation.

44 46 33 10 50 27

20. 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