The heights (in cm) of 90 plants in a garden are given below :

Height (in cm)	Number of Plants
58	20
60	25
62	15
64	8
66	12
74	10

Calculate the mean height.

$\text{Mean} = \dfrac{\sum fx}{\sum f}$

where

f = frequency (Number of plants)

x = observation (Height)

∑fx = 5634 and ∑f = 90

Mean = $\dfrac{5634}{90}$ = 62.6

Hence, mean height = 62.6 cm.