Two-Way Tables — Drills
Two-Way Tables has 8 drill skills. Each one generates fresh questions every time, with a hint and full worked steps, so you can keep practising a single skill until it settles.
What these drills cover
These questions use 3 ideas from the course. Follow any of them for a definition, where it is taught, and what it leads to.
- Percent — Parts per hundred. 37% = 37100 = 0.37.
- Association — A pattern linking the two variables.
- Two-way table — A table of counts sorted by two categorical variables at once.
Completing
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
A two-way table has row totals 30 and 100. Find the grand total.
Worked answer
130
30 + 100 = 130
Problem 2
A two-way table has row totals 25 and 145. Find the grand total.
Worked answer
170
25 + 145 = 170
Reading the graph
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
In a survey of 200 people, 100 said yes. What percent said yes?
Worked answer
50
100200 = 0.5
50%
Problem 2
In a survey of 20 people, 8 said yes. What percent said yes?
Worked answer
40
820 = 0.4
40%
Joint
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
In a two-way table, a count in an edge total is called
Worked answer
a marginal frequency
Row and column totals are marginal frequencies.
Problem 2
In a two-way table, a count in an inner cell is called
Worked answer
a joint frequency
Inner cells are joint frequencies.
Marginal
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
In a two-way table, the total at the end of a row is called
Worked answer
a marginal frequency
Row and column totals are marginal frequencies.
Inner cells are joint frequencies.
Rowpct
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
Of 20 people in one row, 12 answered yes. What percent of that row said yes?
Worked answer
60
1220 = 0.6
60%
Problem 2
Of 40 people in one row, 20 answered yes. What percent of that row said yes?
Worked answer
50
2040 = 0.5
50%
Colpct
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
Of the 20 people in one column, 13 also fall in the first row. What percent of that column is that?
Worked answer
65
1320 ≈ 0.650
≈ 65%
Problem 2
Of the 25 people in one column, 13 also fall in the first row. What percent of that column is that?
Worked answer
52
1325 ≈ 0.520
≈ 52%
Comparing
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
48 of 80 in group 1 and 25 of 50 in group 2 said yes. Which is true?
- No comparison is possible without more information
- A larger share of the first group
- A larger share of the second group
- The shares are equal
Worked answer
A larger share of the first group
Group 1: 4880 = 60%
Group 2: 2550 = 50%
60% > 50%
Problem 2
20 of 40 in group 1 and 40 of 80 in group 2 said yes. Which is true?
- The shares are equal
- A larger share of the second group
- A larger share of the first group
- No comparison is possible without more information
Worked answer
The shares are equal
Group 1: 2040 = 50%
Group 2: 4080 = 50%
Equal shares.
Association
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
37.5 of 50 in one group and 20 of 50 in the other said yes. Is there an association? Answer yes or no.
Worked answer
yes
Group 1: 75%
Group 2: 40%
A gap of 35 points, so yes.
Problem 2
42 of 60 in one group and 12 of 40 in the other said yes. Is there an association? Answer yes or no.
Worked answer
yes
Group 1: 70%
Group 2: 30%
A gap of 40 points, so yes.