Question : Find variance and standard deviation of the following frequency distribution. xFrequency (f)1.5202.0253.5805.0505.5257.2105.35 Solution : Sum of the frequencies \[N=\sum_{i=1}^{N}f_i=215\] (i) Arithmetic average (mean) \[\bar{x}=\frac{\sum_{i=1}^{N}{f_i\ast x_i}}{N}=\frac{30+50+280+250+137.5+72+26.5}{215}=\frac{846}{215}=3.93\] frequency distribution table xFrequency (f)(x-x ̅)(x-x ̅)^2f*(x-x ̅)^21.520-2.435.92118.572.025 -1.93 3.74 93.593.580 -0.43 0.18 15.125.050 1.06 1.13 …
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