Math Problem Statement

solve

In a binomial distribution consisting of 5 independent trials, probabilities of 1 and 2 successes are 0.4096 and 0.2048 respectively. Find the parameter p of the distribution.

Solution

This problem involves a binomial distribution, where the probability of kk successes in nn trials is given by the binomial formula:

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

Given:

  • n=5n = 5 (5 independent trials)
  • Probabilities for 1 and 2 successes are:
    • P(X=1)=0.4096P(X = 1) = 0.4096
    • P(X=2)=0.2048P(X = 2) = 0.2048

We need to find the parameter pp, which is the probability of success in a single trial.

Step 1: Formula for 1 success P(X=1)P(X = 1)

Using the binomial formula for X=1X = 1: P(X=1)=(51)p(1p)4P(X = 1) = \binom{5}{1} p (1 - p)^4 0.4096=5p(1p)40.4096 = 5p (1 - p)^4

Step 2: Formula for 2 successes P(X=2)P(X = 2)

Similarly, for X=2X = 2: P(X=2)=(52)p2(1p)3P(X = 2) = \binom{5}{2} p^2 (1 - p)^3 0.2048=10p2(1p)30.2048 = 10 p^2 (1 - p)^3

Step 3: Solve for pp

Now we have two equations: 5p(1p)4=0.40965p (1 - p)^4 = 0.4096 10p2(1p)3=0.204810 p^2 (1 - p)^3 = 0.2048

By dividing these two equations, we can eliminate some terms and solve for pp:

5p(1p)410p2(1p)3=0.40960.2048\frac{5p (1 - p)^4}{10 p^2 (1 - p)^3} = \frac{0.4096}{0.2048} (1p)2p=2\frac{(1 - p)}{2p} = 2 Multiplying both sides by 2p2p, we get: 1p=4p1 - p = 4p 1=5p1 = 5p p=0.2p = 0.2

Thus, the parameter pp is 0.20\boxed{0.20}, corresponding to option c\text{c}.


Would you like more details or have any other questions?

Here are 5 related questions for further understanding:

  1. How is the binomial distribution derived?
  2. What is the role of the binomial coefficient in this context?
  3. How would the probabilities change if the number of trials nn increased?
  4. Can the binomial formula be used for continuous data?
  5. How would you calculate the expected value of this binomial distribution?

Tip: In binomial problems, always carefully match the formula with the given probability for a certain number of successes!

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Math Problem Analysis

Mathematical Concepts

Probability
Binomial Distribution
Algebra

Formulas

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

Theorems

Binomial Theorem

Suitable Grade Level

Grades 10-12