Math Problem Statement

The manufacturer of a fertilizer guarantees that, with the aid of the fertilizer, 65% of planted seeds will germinate. Suppose the manufacturer is correct. If 7 seeds planted with the fertilizer are randomly selected, what is the probability that at least 6 of Item germinate?

Carry your intermediate computations to at least four decimal places, and round your answer to two decimal places.

Solution

This problem involves finding the probability that at least 6 out of 7 seeds will germinate, given that each seed has a 65% chance of germination. This situation can be modeled using the binomial distribution.

Step 1: Identify the parameters

  • n=7n = 7: the number of trials (seeds).
  • p=0.65p = 0.65: the probability of success on each trial (germination).
  • We want to find P(X6)P(X \geq 6), where XX is the number of seeds that germinate.

Step 2: Define the binomial probability formula

The probability of exactly kk successes in nn independent trials is given by the binomial probability formula:

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

Where:

  • (nk)\binom{n}{k} is the binomial coefficient, calculated as n!k!(nk)!\frac{n!}{k!(n-k)!}.

Step 3: Calculate P(X=6)P(X = 6) and P(X=7)P(X = 7)

  1. For k=6k = 6:

P(X=6)=(76)(0.65)6(10.65)1P(X = 6) = \binom{7}{6} (0.65)^6 (1-0.65)^{1}

  1. For k=7k = 7:

P(X=7)=(77)(0.65)7(10.65)0P(X = 7) = \binom{7}{7} (0.65)^7 (1-0.65)^{0}

Step 4: Compute the probabilities

  1. For k=6k = 6:

P(X=6)=7!6!1!(0.65)6(0.35)P(X = 6) = \frac{7!}{6!1!} (0.65)^6 (0.35)

P(X=6)=7×(0.11602906)×0.35=0.2838P(X = 6) = 7 \times (0.11602906) \times 0.35 = 0.2838

  1. For k=7k = 7:

P(X=7)=7!7!0!(0.65)7=1×(0.07530352)=0.0753P(X = 7) = \frac{7!}{7!0!} (0.65)^7 = 1 \times (0.07530352) = 0.0753

Step 5: Find the total probability P(X6)P(X \geq 6)

P(X6)=P(X=6)+P(X=7)P(X \geq 6) = P(X = 6) + P(X = 7)

P(X6)=0.2838+0.0753=0.3591P(X \geq 6) = 0.2838 + 0.0753 = 0.3591

Final Answer:

The probability that at least 6 of the 7 seeds will germinate is 0.36 (rounded to two decimal places).


Would you like more details or have any questions?

Here are 8 related questions you could explore:

  1. What is the probability that exactly 5 seeds germinate?
  2. How would the probability change if the success rate was 70%?
  3. What is the probability that fewer than 4 seeds germinate?
  4. How do you calculate the binomial coefficient for large numbers?
  5. Can this problem be solved using normal approximation?
  6. How does the binomial distribution apply to real-world situations?
  7. What is the expected number of seeds that will germinate?
  8. How does increasing the number of seeds affect the distribution?

Tip: When working with binomial probabilities, it's helpful to use a calculator or software that handles binomial functions to avoid manual errors, especially with larger numbers.

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Math Problem Analysis

Mathematical Concepts

Probability
Binomial Distribution

Formulas

Binomial probability formula

Theorems

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Suitable Grade Level

Grades 10-12