The Average Height Of 30 Boys Was Calculated To Be 150 Cm. It Was Det

1.	The Average Height Of 30 Boys Was Calculated To Be 150 Cm. It Was Detected Later That One Value Of 165 Cm Was Wrongly Copied As 135 Cm For The Computation Of The Mean. Find The Correct Mean?
Answer» Calculated average height of 30 boys = 150 CM. Incorrect sum of the heights of 30 boys = (150 × 30)cm = 4500 cm. Correct sum of the heights of 30 boys = (incorrect sum) - (wrongly COPIED item) + (actual item) = (4500 - 135 + 165) cm = 4530 cm. Correct mean = correct sum/number of boys = (4530/30) cm = 151 cm. Hence, the correct mean height is 151 cm. Calculated average height of 30 boys = 150 cm. Incorrect sum of the heights of 30 boys = (150 × 30)cm = 4500 cm. Correct sum of the heights of 30 boys = (incorrect sum) - (wrongly copied item) + (actual item) = (4500 - 135 + 165) cm = 4530 cm. Correct mean = correct sum/number of boys = (4530/30) cm = 151 cm. Hence, the correct mean height is 151 cm.

The Average Height Of 30 Boys Was Calculated To Be 150 Cm. It Was Detected Later That One Value Of 165 Cm Was Wrongly Copied As 135 Cm For The Computation Of The Mean. Find The Correct Mean?

Answer»

Calculated average height of 30 boys = 150 CM.

Incorrect sum of the heights of 30 boys

= (150 × 30)cm

= 4500 cm.

Correct sum of the heights of 30 boys

= (incorrect sum) - (wrongly COPIED item) + (actual item)

= (4500 - 135 + 165) cm

= 4530 cm.

Correct mean = correct sum/number of boys

= (4530/30) cm

= 151 cm.

Hence, the correct mean height is 151 cm.

Calculated average height of 30 boys = 150 cm.