Q.The number of children in 20 families is recorded below. Prepare a discrete frequency distribution using tally marks. 2, 3, 4, 2, 3, 4, 5, 4, 3, 2, 4, 5, 3, 4, 6, 4, 3, 5, 6, 4

For a discrete variable like the number of children, each distinct value is tallied and counted to form the frequency distribution.

Counting how many times each value from 2 to 6 occurs gives the frequency of each, summing to the 20 families.

The variable (number of children) is discrete, so each distinct value is listed and tallied.

Going through the 20 figures and tallying each value:

Verification (dual-check). The frequencies must add up to the total number of families: 3 + 5 + 7 + 3 + 2 = 20, which matches the 20 families given — confirming no figure was missed or double-counted.

Cross-check by counting each value independently. Count of 2s: positions give 2, 2, 2 → 3. Count of 3s: 3, 3, 3, 3, 3 → 5. Count of 4s: 4, 4, 4, 4, 4, 4, 4 → 7. Count of 5s: 5, 5, 5 → 3. Count of 6s: 6, 6 → 2. Total 3+5+7+3+2 = 20, matching the 20 raw figures — the distribution is correct.

The commonest error is a miscount from the tally — always cross-check that the frequencies sum to the total number of observations (here 20). Forgetting to include a value that appears (or adding one that does not) shows up immediately as a wrong total.