QUIZ 2 - Frequency Distributions and Charts
Q1. Based on the histogram above:
 Class width?
3
(4-1 or 7-4 or 10-7)
 Sample size?
27
(calculate frequencies ex. 4+2+6+3+7+5)
Q2 Based on the histogram above:
 what is the frequency of the class containing the value 2?
3
(the data value 2 is between 1-7 on the x axis (first bar) which correlates to 3 on
frequency/y-axis)
Q3 Suppose 55 students were asked how many courses they were taking this semester. The
results are shown in the (incomplete) table below. Fill in the blank cells to complete the table.
Round relative frequencies to 3 decimal places.
Number of courses
Frequency
Relative frequency
1
11
0.2
2
16
0.291 (16/55)
3
28
0.509 (28/55)
Q4 Find the missing value in the following frequency distribution table.
Class
Frequency
Cumulative
Frequency Percent
20 - 24
5
10.000%
25 - 29
7
24.000%
30 - 34
19
62.000%
35 - 39
6
74.000%
40 - 44
4
X
45 - 49
9
100.000%
X = 82.000% (add all the frequencies up until 4 then divide by the total ex 5+7+19+6+4 / 50)
Q5 Given a single set of quantitative data, choose the best type of graph to represent the data
 histogram
Q6 Given the following bivariate data:
x
3.50
4.25
4.50
4.75
5.00
y
55
55
55
80
80
a) Plot each point in the graph below.
b) The linear relationship between the two variables is:
positive
Q7 Your company is trying to optimize the battery for a new product, and your team has been
investigating the recharge cycle. You want to make sure that the battery does not overheat
during recharge. You keep track of the temperature of the battery as it charges. Your data is
displayed in the relative cumulative frequency chart below.
Estimate the proportion of batteries that charged with a temperature of 90 degrees or
less. (Enter your answer as a decimal between 0 and 1)
 0.25 (look at frequency at 90 degrees; it is 0.25 which is everything at or below 90 degrees)
Estimate the proportion of batteries that charged with a temperature above 92 degrees. (Enter
your answer as a decimal between 0 and 1)
 0.6 (total is 1; 92 degrees is 0.4; so, 1-0.4 = 0.6 which is everything above 92 degrees)