Elementary Statistics (12th Edition)

a) $P(X=0)={12\choose 0} \cdot (0.55)^{12}\cdot (0.45)^0=0.000766.$ b)$P(X\geq1)=1-P(X=0)=1-0.000766=0.999234$ c)$P(X\leq1)=P(X=0)+P(X=1)={12\choose 0} \cdot (0.55)^{12}\cdot (0.45)^0+{12\choose 1} \cdot (0.55)^{11}\cdot (0.45)^1=0.000766+0.00752=0.008286$ d)The probability of c) is very low, which suggets that the share value might have been wrong.