Completing a two-way table Revision Card

AI generatedProbabilityKey Stage 3

Completing a two-way table.

Probability = favourable outcomes ÷ all outcomes when individual outcomes are equally likely.
A probability lies between 0 and 1; complementary probabilities sum to 1.
Experimental relative frequency estimates probability and can vary between samples.

Example 1

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	8	?	13
No club	?	4	?
Total	?	?	23

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 5; no club/walk 6; no club total 10; walk total 14; bus total 9.

Completed counts

	Walk	Bus	Total
Club	8	5	13
No club	6	4	10
Total	14	9	23

Black: given data. Blue: working we add.

Example 2

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	9	?	14
No club	?	4	?
Total	?	?	25

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 5; no club/walk 7; no club total 11; walk total 16; bus total 9.

Completed counts

	Walk	Bus	Total
Club	9	5	14
No club	7	4	11
Total	16	9	25

Black: given data. Blue: working we add.

Your turn

Question 1

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	10	?	15
No club	?	4	?
Total	?	?	27

Check answer

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 5; no club/walk 8; no club total 12; walk total 18; bus total 9.

Completed counts

	Walk	Bus	Total
Club	10	5	15
No club	8	4	12
Total	18	9	27

Black: given data. Blue: working we add.

Question 2

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	11	?	16
No club	?	4	?
Total	?	?	29

Check answer

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 5; no club/walk 9; no club total 13; walk total 20; bus total 9.

Completed counts

	Walk	Bus	Total
Club	11	5	16
No club	9	4	13
Total	20	9	29

Black: given data. Blue: working we add.

Question 3

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	12	?	18
No club	?	4	?
Total	?	?	32

Check answer

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 6; no club/walk 10; no club total 14; walk total 22; bus total 10.

Completed counts

	Walk	Bus	Total
Club	12	6	18
No club	10	4	14
Total	22	10	32

Black: given data. Blue: working we add.

Question 4

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	13	?	19
No club	?	4	?
Total	?	?	34

Check answer

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 6; no club/walk 11; no club total 15; walk total 24; bus total 10.

Completed counts

	Walk	Bus	Total
Club	13	6	19
No club	11	4	15
Total	24	10	34

Black: given data. Blue: working we add.

Question 5

Complete the missing entries.

Travel and club attendance

	Walk	Bus	Total
Club	14	?	20
No club	?	5	?
Total	?	?	37

Check answer

Club and bus

Subtract the known entry from its row total.

No club and walk

Find the second row total, then its missing entry.

Club/bus 6; no club/walk 12; no club total 17; walk total 26; bus total 11.

Completed counts

	Walk	Bus	Total
Club	14	6	20
No club	12	5	17
Total	26	11	37

Black: given data. Blue: working we add.