In this problem, we will approximate a binomial dis- tribution by a normal distribution. From looking at the pmfs of the binomial distribution, for large values of n the histogram of the binomial pmf looks “bell-shaped”. It turns out that the normal distribution is a good approximation for the binomial approximation for large n. It also works for small n as long as p is not too far from 0.5. For convenience, we will let q = 1 − p.

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Chapter1: Combinatorial Analysis
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Please help with problems a, b, and c: 

In this problem, we will approximate a binomial dis- tribution by a normal distribution. From looking at the pmfs of the binomial distribution, for large values of n the histogram of the binomial pmf looks “bell-shaped”. It turns out that the normal distribution is a good approximation for the binomial approximation for large n. It also works for small n as long as p is not too far from 0.5. For convenience, we will let q = 1 − p.

(a) Let \( X \sim \text{Binomial}(25, 0.4) \). Compute \( P(X = 10) \).

(b) We will approximate \( X \) with a normal random variable. Let \( Y \) be a normal random variable with the same mean and variance as \( X \). Compute \( P(9.5 \leq Y \leq 10.5) \). We will use this as an approximation for \( P(X = 10) \).

(c) Briefly explain why we used the event \( (9.5 \leq Y \leq 10.5) \) to approximate the event \( (X = 10) \).
Transcribed Image Text:(a) Let \( X \sim \text{Binomial}(25, 0.4) \). Compute \( P(X = 10) \). (b) We will approximate \( X \) with a normal random variable. Let \( Y \) be a normal random variable with the same mean and variance as \( X \). Compute \( P(9.5 \leq Y \leq 10.5) \). We will use this as an approximation for \( P(X = 10) \). (c) Briefly explain why we used the event \( (9.5 \leq Y \leq 10.5) \) to approximate the event \( (X = 10) \).
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X~Bin(n,p)


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