Question

Q. 7. The average height of 30 students is 150 cm. It was detected later that one value of 165 cm was
wrongly copied as 135 cm for the computation of mean. Find the correct mean.
Tftha​

Answer 1

Answer:

Total sum of boys height:- 30x150=4500 cm.

Difference of wrongly copied:- 165–135=30 cm.

Correct Total sum of boys height:- 4500+30=4530 cm.

Correct average:-4530÷30=151 cm.

Answer 2

Answer:

Mean height of 30 students = 150cm

Total height of 30 students = (150 × 30) cm = 4500 cm

But 165 cm was noted as 135 cm

correct total height of 30 students = (4500 - 135 + 165) = 4530 cm

$correct \: mean \: = \: \frac{4530 \: cm}{30} \: = 151cm$

Hope it helps you ⛄