Probability No Favor
1. **Problem Statement:**
Suppose 40% of a large population of registered voters favor the candidate Nimal. A random sample of 5 voters is selected. We want to find the probability that none of the 5 voters favor Nimal.
2. **Identify the distribution:**
This is a binomial probability problem where:
- Number of trials $n = 5$
- Probability of success (favoring Nimal) $p = 0.4$
- Probability of failure $q = 1 - p = 0.6$
- Number of successes $k = 0$
3. **Formula:**
The binomial probability formula is:
$$P(X = k) = \binom{n}{k} p^k q^{n-k}$$
where $\binom{n}{k} = \frac{n!}{k!(n-k)!}$ is the binomial coefficient.
4. **Calculate the probability:**
For $k=0$,
$$P(X=0) = \binom{5}{0} (0.4)^0 (0.6)^5 = 1 \times 1 \times (0.6)^5 = (0.6)^5$$
5. **Evaluate:**
$$ (0.6)^5 = 0.6 \times 0.6 \times 0.6 \times 0.6 \times 0.6 = 0.07776 $$
6. **Interpretation:**
The probability that none of the 5 voters favor Nimal is approximately 0.07776 or 7.776%.