Practicing Success
In a box containing 100 bulbs, 10 are defective. Then the probability, that out of a sample of 5 bulbs none is defective, is: |
$10^{-1}$ $\left(\frac{1}{2}\right)^5$ $\left(\frac{9}{10}\right)^5$ $\left(\frac{9}{10}\right)$ |
$\left(\frac{9}{10}\right)^5$ |
D → defective bulb $\overline{D}$ → bulb is not defective P(D) = $\frac{10}{100} = \frac{1}{10}$ $P(\overline{D}) = 1 - P(D) = \frac{9}{10}$ for 5 bulbs P(none is defective) = ${}^5 C_5 (P(\overline{D}))^5$ $=\frac{9^5}{10^5}$ |