NCERT Class XI Mathematics - Statistics - Solutions
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Question : 26
Total: 34
The following is the record of goals scored by team A in a football session:
For the team B, mean number of goals scored per match was 2 with a standard deviation 1.25 goals. Find which team may be considered more consistent?
| No. of goals scored | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| No. of matches | 1 | 9 | 7 | 5 | 3 |
For the team B, mean number of goals scored per match was 2 with a standard deviation 1.25 goals. Find which team may be considered more consistent?
Solution:
For team A :
Mean(
)
Σ f i x i
( σ A ) √
− (
) 2
=√
− (
) 2
=√ 5.2 − 4 √ 1.2
∴ C.V. of team A =
C.V. of team B=
Since C.V. of team A < C.V. of team B. Thus team A is more consistent.
| | | | |
|---|---|---|---|
| 0 | 1 | 0 | 0 |
| 1 | 9 | 9 | 9 |
| 2 | 7 | 14 | 28 |
| 3 | 5 | 15 | 45 |
| 4 | 3 | 12 | 48 |
| 25 | 50 | 130 |
Mean
=
=
∴ C.V. of team A =
C.V. of team B=
Since C.V. of team A < C.V. of team B. Thus team A is more consistent.
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