The data are as follows. The best point estimate for the population standard deviation, σ, is the sample standard deviation, s. Recall the formula for calculating s is s=√((C(xi)-(x) 
a) s = √((C(xᵢ)-(x)/n-1 
b) s = √((C(xᵢ)-(x)/n 
c) s = √((C(xᵢ)-(x) 
d) s = √((C(xᵢ)-(x)/n+1