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5 students of a class have an average height 150 cm and variance 18 cm². A new student, whose height is 156 cm, joined them. The variance (in cm²) of the height of these six students is:
- 16
- 22
- 20
- 18
Correct answer: 20
Solution
The variance of a set of data changes when a new value is added, and in this case, the new student's height is above the average, which increases the overall variance. The calculation shows that the new variance for the six students is 20 cm².
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