Answer
$μ=520.2$
$σ=117.3$
Work Step by Step
$x_1=$ First Class Midpoint = 250
$x_2=$ Second Class Midpoint = 350
$x_3=$ Third Class Midpoint = 450
$x_4=$ Fourth Class Midpoint = 550
$x_5=$ Fifth Class Midpoint = 650
$x_6=$ Sixth Class Midpoint = 750
$μ=\frac{Σx_if_i}{Σf_i}=\frac{250\times36305+350\times193968+450\times459010+550\times467855+650\times286518+750\times104334}{1548020}=520.2$
$σ=\sqrt {\frac{Σ(x_i-μ)^2f_i}{Σf_i}}=\sqrt {\frac{(250-520.2)^2\times36305+(350-520.2)^2\times193968+(450-520.2)^2\times459010+(550-520.2)^2\times467855+(650-520.2)^2\times286518+(750-520.2)^2\times104334}{1548020}}=117.3$
