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Two-way tables

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Interpreting results

Two-way tables

A frequency table shows one thing. A two-way table shows two at once โ€” how a hockey team did, split by home and away, all in one grid.

A cell counts what is in BOTH its row and its columnWinDrawLoseTotalHome73212Away34512Total107724Home games lost = 2 ยท the bottom-right 24 is the grand total
Row totals and column totals must both reach the same grand total.

From one set of data to two

A FREQUENCY TABLE is good for showing ONE piece of information โ€” how many people sent 0โ€“9 texts, 10โ€“19 texts, and so on. But often you want two things at once. A TWO-WAY TABLE records two sets of DISCRETE DATA by putting one in the rows and the other in the columns.

Reading a cell

Each cell sits where a row and a column meet, and it counts the things that are in BOTH. For a hockey team's season: Win Draw Lose Total Home 7 3 2 12 Away 3 4 5 12 Total 10 7 7 24 Home games lost? Go along the 'Home' row to the 'Lose' column: 2.

The totals row and column

The last row and last column hold the TOTALS. โ€ข Games drawn altogether: the 'Total' row, 'Draw' column โ†’ 7. โ€ข Games played altogether: bottom-right corner โ†’ 24. That bottom-right number is the grand total. It should equal the row totals added up AND the column totals added up โ€” a built-in check.

Filling in a missing value

Because every row and column adds to its total, you can work out any missing cell. If the Away row shows 3 wins, 4 draws and a total of 12, then the losses must be 12 โˆ’ 3 โˆ’ 4 = 5 Subtract what you know from the total.

Worked examples

How many home games were lost?

  1. Find the 'Home games' row.
  2. Follow it to the 'Lose' column.

Answer: 2

How many away games were won?

  1. Find the 'Away games' row.
  2. Follow it to the 'Win' column.

Answer: 3

How many games were drawn altogether?

  1. Go to the 'Total' row.
  2. Read the 'Draw' column.

Answer: 7

How many games were played in the season?

  1. The grand total is the bottom-right cell.

Answer: 24

Filling a gap: away games with 3 wins, 4 draws, 12 total

  1. The row must add to 12.
  2. 12 โˆ’ 3 โˆ’ 4 = 5.

Answer: 5 losses

Checking a two-way table

  1. Add the row totals.
  2. Add the column totals.
  3. Both should equal the grand total.

Answer: Both give 24, so the table is consistent

Where you see this in real life

  • Exam results are often published as a two-way table of grade against subject, so you can compare in either direction.
  • A shop's sales table splits takings by branch and by month, which is how they spot a branch having a bad quarter.

Key words

Two-way table
a table recording two sets of data, in rows and columns
Frequency table
a table showing how often each value occurs
Discrete data
data you count, in separate whole values
Total
the sum of a row or column
Cell
one box in a table, where a row meets a column