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Assume that each of the \( n \) trials is independent and that \( p \) is the probability of success on a given trial. Use the binomial probability formula to find \( P(x) \).

Given:
[tex]\[ n=16, \, x=2, \, p=\frac{1}{4} \][/tex]

[tex]\[ P(x)= \square \][/tex]

(Round to three decimal places as needed.)



Answer :

GinnyAnswer
Certainly! Let's solve the problem step by step using the binomial probability formula.

Given:
- Number of trials (\( n \)) = 16
- Number of successes (\( x \)) = 2
- Probability of success on a given trial (\( p \)) = \( \frac{1}{4} \)

We use the binomial probability formula:

[tex]\[ P(X = x) = \binom{n}{x} \cdot p^x \cdot (1-p)^{n-x} \][/tex]

Here, \( \binom{n}{x} \) is the binomial coefficient, which is calculated as:

[tex]\[ \binom{n}{x} = \frac{n!}{x!(n-x)!} \][/tex]

Substitute the given values into the binomial coefficient formula:

[tex]\[ \binom{16}{2} = \frac{16!}{2!(16-2)!} = \frac{16!}{2! \cdot 14!} \][/tex]

After canceling out common factorial terms, this simplifies to:

[tex]\[ \binom{16}{2} = \frac{16 \times 15}{2 \times 1} = 120 \][/tex]

Next, calculate the probability terms:

[tex]\[ p^x = \left(\frac{1}{4}\right)^2 = \frac{1}{16} \][/tex]

[tex]\[ (1-p)^{n-x} = \left(1 - \frac{1}{4}\right)^{16-2} = \left(\frac{3}{4}\right)^{14} \][/tex]

Now, putting it all together in the binomial probability formula:

[tex]\[ P(X = 2) = 120 \cdot \frac{1}{16} \cdot \left(\frac{3}{4}\right)^{14} \][/tex]

After evaluating the arithmetic:

[tex]\[ P(X = 2) = 120 \cdot \frac{1}{16} \cdot 0.0953 \quad \text{(rounded to 4 decimal places for simplicity)} \][/tex]

Finally, multiplying all factors together gives:

[tex]\[ P(X = 2) \approx 0.13363461010158062 \][/tex]

Rounded to three decimal places, the probability is:

[tex]\[ P(X = 2) \approx 0.134 \][/tex]

So, the probability of getting exactly 2 successes in 16 trials, with each trial having a success probability of \( \frac{1}{4} \), is approximately 0.134.

[tex]\[ \boxed{0.134} \][/tex]

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