Math Problem Statement

Using the binomial probability distribution, when p=0.30 and n=14 what is P(X=4)?

Solution

To find the probability P(X=4)P(X = 4) using the binomial probability distribution formula, we will use the following formula:

P(X=k)=(nk)pk(1p)nkP(X = k) = \binom{n}{k} p^k (1 - p)^{n-k}

Where:

  • n=14n = 14 (number of trials),
  • p=0.30p = 0.30 (probability of success on a single trial),
  • X=k=4X = k = 4 (number of successes).

We need to calculate (nk)\binom{n}{k}, which is the number of combinations (the binomial coefficient), followed by the rest of the formula:

P(X=4)=(144)(0.30)4(10.30)144P(X = 4) = \binom{14}{4} (0.30)^4 (1 - 0.30)^{14-4}

P(X=4)=(144)(0.30)4(0.70)10P(X = 4) = \binom{14}{4} (0.30)^4 (0.70)^{10}

Now, let's compute this.

First, calculate (144)\binom{14}{4}:

(144)=14!4!(144)!=14×13×12×114×3×2×1=1001\binom{14}{4} = \frac{14!}{4!(14-4)!} = \frac{14 \times 13 \times 12 \times 11}{4 \times 3 \times 2 \times 1} = 1001

Next, calculate the terms:

0.304=0.00810.30^4 = 0.0081 0.7010=0.02824750.70^{10} = 0.0282475

Now, calculate P(X=4)P(X = 4):

P(X=4)=1001×0.0081×0.0282475P(X = 4) = 1001 \times 0.0081 \times 0.0282475

Let me compute this final value.The probability P(X=4)P(X = 4) when p=0.30p = 0.30 and n=14n = 14 is approximately 0.2290.229, or 22.9%.

Would you like more details, or do you have any other questions?

Here are some related questions to expand on this topic:

  1. How would the probability change if pp increased to 0.40?
  2. What is the cumulative probability P(X4)P(X \leq 4)?
  3. How can we interpret binomial probabilities in real-world scenarios?
  4. What is the expected value and variance for this binomial distribution?
  5. How do you calculate P(X5)P(X \geq 5) using complementary probabilities?

Tip: The sum of all probabilities in a binomial distribution for a given nn must always equal 1.

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Math Problem Analysis

Mathematical Concepts

Binomial Probability Distribution
Combinatorics
Probability

Formulas

P(X = k) = \binom{n}{k} p^k (1 - p)^{n-k}
\binom{n}{k} = \frac{n!}{k!(n-k)!}

Theorems

Binomial Theorem

Suitable Grade Level

Grades 10-12