QUESTION 3
[20 Marks]
A large statistics class takes a midsemester examination worth a total of 100 points. The
following is a random sample of 20 students' scores from the class.
Score of 98 points: 2 students
Score of 95 points: 1 student
Score of 92 points: 3 students
Score of 88 points: 4 students
Score of 87 points: 2 students
Score of 85 points: 2 students
Score of 81 points: 1 student
Score of 78 points: 2 students
Score of 73 points: 1 student
Score of 72 points: 1 student
Score of 65 points: 1 student
(a) Calculate the standard deviation of the exam scores for the students in this sample to
the nearest tenth of a point. Show all your calculations.
(15 Marks)
s=
Hint:
(b) What is the mode and median class marks?
(5 Marks)
QUESTION 4
[20 Marks]
(a) A Real Estate Agent tells you that the average cost of houses in a town is NAD2,176,000.
You want to know how much the prices of the houses may vary from this average. What
measurement do you need?
(2 Marks)
A. standard deviation
B. interquartile range
C. variance
D. percentile
(b) To the nearest thousandth, what is the mean of the following data set? 0.003, 0.045, 0.58,
0.687, 1.25, 10.38, 11.252, 12.001
(2 Marks)
(c) To the nearest tenth, what is the median of the following data set? 18, 21, 17, 18, 16, 15.5,
12, 17, 10, 21, 17.
(2 Marks)
(d) The starting salaries (in dollars) of a random sample of 125 university graduates were
analysed. The following descriptive statistics were calculated and typed into a report:
Mean: 24,329
Median: 20,461
Variance: 4,683,459
Minimum: 18,958
3