Question

In eight throws of a die, 5 or 6 is considered as a success, then the standard deviation is ________ .

• A. 1.33

Answer 1

The correct option is A 1.33
p = The probability of success $=\frac{2}{6}=\frac{1}{3}$
q = The probability of failure$=1-p=1-\frac{1}{3}=\frac{2}{3}$

n = Number of throws = 8

Variance $=npq=8\times \frac{1}{3}\times \frac{2}{3}=\frac{16}{9}$

Hence, Standard deviation $=\sqrt{Variance}=\sqrt{\frac{16}{9}}=\frac{4}{3}$