Answer
mean = 5.08
variance = 6.8506
standard deviation = 2.6174
It is a sample statistic.
Work Step by Step
$mean =∑fx \div f = 254/50= 5.08$
$variance ={∑(fx^2) –[∑(fx)^2/N]}/(n-1)$
$= [1626- (64516/50)] / 49 $
$= 6.8506$
$standard \ deviation =\sqrt 6.8506 = 2.6174$
