Two groups of children were scored on knowledge of numbers.
Low number-talk parents:
High number-talk parents:
Complete the frequency distribution table giving and for each score .
Set up the tally in a fixed order. List the possible scores through and pass through the data once, marking each value. Working score-by-score instead (scanning the list five times) is what usually causes a value to be counted twice or missed.
Tally the low group. Going through :
appears at positions , , → times
appears at positions → times
appears at positions → times
appears at positions → times
appears at position → time
Tally the high group. Going through :
→ times; → time; → times; → times; → times.
Assemble the table.
| 5 | 1 | 5 |
| 4 | 2 | 6 |
| 3 | 4 | 3 |
| 2 | 5 | 1 |
| 1 | 3 | 0 |
| Total | 15 | 15 |
Check both columns against n. ✓ and ✓. This total is the essential check: a frequently circulated version of this table lists the low column as , which also sums to but swaps the counts of and — only re-tallying, not the total, catches that.
Read the comparison the table is for. The low group piles up at scores – (eight of fifteen children) while the high group piles up at – (eleven of fifteen), so the distributions are shifted rather than merely differently spread — which is the point the original study was making.
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