Q.In a city 45 families were surveyed for the number of Cell phones they used. Prepare a frequency array based on their replies as recorded below.
1 3 2 2 2 2 1 2 1 2 2 3 3 3 3
3 3 2 3 2 6 1 6 2 1 5 1 5 3
2 4 2 7 4 2 4 3 4 2 0 3 1 4 3
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Start your 14-day free trial to unlock the full solution →The number of cell phones a family uses is a discrete variable, so the right tool is a frequency array: list every distinct value 0–7 and count how many families reported it. Tallying the full recorded data gives 0→1, 1→7, 2→14, 3→12, 4→5, 5→2, 6→2, 7→1, totalling 44 families — one short of the "45 families" the question states (a genuine inconsistency in the printed data, disclosed below rather than papered over).
Concept: frequency array for a discrete variable
When a variable can take only a few separate whole-number values (0, 1, 2, 3 …), we do not form class intervals. Instead we prepare a frequency array: each distinct value of the variable is written down and against it we place the number of items (here, families) taking that value.
Method
- Identify the distinct values that appear in the replies (0 through 7).
- Tally how many times each value occurs across the full recorded data.
- Enter the counts as frequencies.
Tally (from the full recorded data, all three rows)
Reading every value in the three data rows exactly as printed:
| Number of cell phones (X) | Number of families (f) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 14 |
| 3 | 12 |
| 4 | 5 |
| 5 | 2 |
| 6 | 2 |
| 7 | 1 |
| Total | 44 |
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