Question

the mean height of24 students was found to be 156cm .It was discovered later on that the reading 143cm was wrongly read as 185cm .Find the correct mean

Answer 1

ANSWER
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$avg \: = \frac{sum \: of \: all \: obs.}{no.of \: obs.}$

Mean Height = 156 cm
Total no. of student = 24

Sum of All heights = 156 × 24
= 3744 cm

Since it was 143 not 185 so reading is more by 42

Corrected sum of Height = 3744 - 42
= 3702

Mean Height = 3702 ÷ 24

=> 154.25 cm

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Answer 2

Mean Height = 156 cm

Total no. of student = 24

Sum of All heights = 156 × 24

= 3744 cm

Since it was 143 not 185 so reading is more by 42

Corrected sum of Height = 3744 - 42

= 3702

Mean Height = 3702 ÷ 24

=> 154.25 cm