Solutions - 5080-01

(1) Identify the binomial distribution:

$X\sim \text{Bin}(50,0.9)$ where $X$ = number of good paper clips.

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(2) Express and evaluate $P[X\ge 45]$:

$$\begin{array}{c}P[X\ge 45]=\sum _{k=45}^{50}\left(\genfrac{}{}{0px}{}{50}{k}\right){(0.9)}^k{(0.1)}^{50-k}\\ \\ \gg \gg \approx 0.6161\end{array}$$