Question 868154
Note : Your probabilities do not sum to 1 but rather 0.9999.
Find the expected value {{{mu}}}
{{{mu=0(0.6274)+1(0.3102)+2(0.0575)+3(0.0047)+4(0.0001)}}}
{{{mu=0.4397}}}
Now find the variance,
{{{Var=sum(x^2*P(x)-mu^2)}}}
{{{Var=0(0.6274)+1(0.3102)+4(0.0575)+9(0.0047)+16(0.0001)-0.1933)}}}
{{{Var=0.5841-0.1933)}}}
{{{Var=0.3908}}}
{{{sigma=sqrt(Var)}}}
{{{sigma=0.6251}}}