लघु विधि द्वारा माध्य , प्रसरण तथा मानक विचलन ज्ञात कीजिए :
`{:("ऊँचाई ( सेमी )",70-75,75-80,80-85,85-90,90-95,95-100,100-105,105-110,110-115),("बच्चों की संख्या"," "3," "4," "7," "7," "15," "9," "6," "6," "3 ):}`

Explanation

यहाँ कल्पित माध्य , `A = 92.5`

माध्य , ` bar x = A + (sum f_(i)u_(i))/N xx h`

` = 92.5 + 6/60 xx 5`

` = 92.5 + 0.5 = 93`

प्रसरण , `sigma ^(2) = h^(2)/N^(2) [Nsumf_(i)u_(i)^(2)-(sumf_(i)u_(i))^(2)]`

` = 25/3600[60xx254 -(6)^(2)]`

` = 1/144 [15240 - 36]`

` = 1/144 xx 1504 = 105.58`

मानक विचलन
, ` sigma = sqrt(105.58) = 10.27`.