Question
Compute the variance and S.D. for the following data:
✓
Answer
$\bar{x}=\frac{\sum f_i x_i}{N}=\frac{2351}{50}=47.02$
$\operatorname{Var}( X )=\sigma_x^2=\frac{\sum f _i x_i^2}{ N }-(\bar{x})^2$
$=\frac{119553}{50}-(47.02)^2=2391.06-2210.88=180.18$
S.D. $=\sigma_x=\sqrt{\operatorname{Var}(X)}=\sqrt{180.18}=13.42$
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