Name: 
 

Chapter 1: Associations between variables


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
What kind of data is the following?

The heights of basketball players.
A
numerical: discrete
B
numerical: continuous
C
categorical: nominal
D
categorical: ordinal
E
None of the above
 

 2. 
The following incomplete two-way table describes a gardener’s experiment with two fertilisers. She adds fertiliser A to some plants and fertiliser B to the other plants. She then compares the different numbers of tomatoes produced by the two sets of plants.

How many plants using fertiliser B produced twenty or less tomatoes?

 
Number of fruit
 
 
0-20
21-40
41+
Total
Fertiliser A used
6
18
 
41
Fertiliser B used
   
49
Total:
 
42
34
 
A
6
B
7
C
8
D
9
E
10
 

 3. 
Students at different year levels are asked their future choice of career. The results are summarised in the table below.

Work type
Year 7-8
Year 9-10
Year 10-12
Trade
18   
9     
7     
Clerical
3   
7     
8     
Manual
14   
8     
4     
Professional
14   
13     
17     

What percentage of Year 7-8 students would like a manual type of career?
A
24%
B
26%
C
29%
D
54%
E
57%
 

 4. 
Students at different year levels are asked their future choice of career. The results are summarised in the table below.

Work type
Year 7-8
Year 9-10
Year 10-12
Trade
16   
9     
7     
Clerical
3   
7     
8     
Manual
14   
8     
4     
Professional
14   
13     
17     

If a student from the school is chosen at random, what is the probability they are in Year 9-12 and would like a clerical career?
A
0.13
B
0.15
C
0.17
D
0.18
E
0.2
 

 5. 
A false positive is a
A
positive result that is wrong.
B
positive result that is correct.
C
negative result that is wrong.
D
negative result that is correct.
E
negative result that may be correct.
 

 6. 
A test for a certain disease is correct 91% of the time. The disease occurs in 3% of the population. Display this information in a two-way table. Use this table to find the probability that

(a) You will not have the disease and be diagnosed that you have it.
(b) You will have the disease but be diagnosed as not having it.
A
(a) 3%
(b) 9%
B
(a) 9%
(b) 3%
C
(a) 0.27%
(b) 8.73%
D
(a) 8.73%
(b) 0.27%
E
(a) 91%
(b) 91%
 

 7. 
What kind of a relationship could be concluded between the x and y variables from the scatter plot below?

     mc007-1.jpg
A
No relationship
B
Weak positive
C
Weak negative
D
Strong positive
E
Strong negative
 

 8. 
The covariance of x and y is –144.12 and their standard deviations are 17.806 and 11.906 respectiviely. What is their correlation coefficient?
A
–0.70
B
–0.68
C
0.68
D
–0.66
E
0.66
 

 9. 
When a scatterplot is drawn, the points form a perfect straight line with gradient mc009-1.jpg. What is the correlation coefficient?
A
0
B
–1
C
1
D
mc009-2.jpg
E
mc009-3.jpg
 

 10. 
Calculate Pearson’s correlation coefficient for the data in the table below.

x
21
8
49
40
41
56
10
26
46
19
y
24
10
21
43
37
46
8
29
11
20
A
–0.68
B
0.64
C
–0.64
D
0.61
E
–0.61
 

 11. 
A student compared two variables, calculating the correlation coefficient to be –0.27. This means there is ...
A
no relationship
B
a weak negative relationship
C
a moderate negative relationship
D
a strong negative relationship
E
a perfect negative relationship
 

Problem
 

 12. 
In two different clubs, the membership was broken down according to age groups as follows.
Display the data in a two-way table.

                pr012-1.jpg
                Group 1: Aged 15-17                 Red: Frangipani Club
                Group 2: Aged 18-21                 Blue: Ironing Club
                Group 3: Aged 22-29
                Group 4: Aged 30-35
                Group 5: Aged 36+
 



 
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