Math Problem Statement

A pharmaceutical company receives large shipments of ibuprofen tablets and uses this acceptance sampling plan: randomly select and test 29 tablets, then accept the whole batch if there is at most one that doesn't meet the required specifications. If a particular shipment of thousands of ibuprofen tablets actually has a 1% rate of defects, what is the probability that this whole shipment will be accepted?

(Report answer as a decimal value accurate to four decimal places.) P(accept shipment) = 

Solution

To solve this, we need to calculate the probability that a shipment of ibuprofen tablets is accepted under the given sampling plan, where the acceptance rule is:

  • Randomly select 29 tablets.
  • Accept the shipment if at most 1 tablet is defective.

The shipment is accepted if 0 or 1 defective tablet is found in the sample of 29. The number of defective tablets follows a binomial distribution, where:

  • n=29n = 29 (the sample size),
  • p=0.01p = 0.01 (the probability that any individual tablet is defective),
  • XX is the random variable representing the number of defective tablets in the sample.

The probability that exactly kk defective tablets are found follows the binomial probability mass function (PMF):

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

For this case, the shipment is accepted if X1X \leq 1. So, we need to calculate:

P(X=0)+P(X=1)P(X = 0) + P(X = 1)

Step 1: Calculate P(X=0)P(X = 0)

P(X=0)=(290)(0.01)0(0.99)29=1(0.99)29P(X = 0) = \binom{29}{0} (0.01)^0 (0.99)^{29} = 1 \cdot (0.99)^{29}

Using a calculator: P(X=0)0.7397P(X = 0) \approx 0.7397

Step 2: Calculate P(X=1)P(X = 1)

P(X=1)=(291)(0.01)1(0.99)28=290.01(0.99)28P(X = 1) = \binom{29}{1} (0.01)^1 (0.99)^{28} = 29 \cdot 0.01 \cdot (0.99)^{28}

Using a calculator: P(X=1)290.010.73970.2145P(X = 1) \approx 29 \cdot 0.01 \cdot 0.7397 \approx 0.2145

Step 3: Calculate the total probability

P(accept shipment)=P(X=0)+P(X=1)=0.7397+0.2145=0.9542P(\text{accept shipment}) = P(X = 0) + P(X = 1) = 0.7397 + 0.2145 = 0.9542

Thus, the probability that the shipment will be accepted is approximately:

P(accept shipment)=0.9542P(\text{accept shipment}) = 0.9542

So, the final answer is:

0.9542\boxed{0.9542}

Would you like any further details or explanations on the calculation? Here's a set of related questions for further study:

  1. What is the expected number of defective tablets in the sample of 29?
  2. How would the acceptance probability change if the defect rate were 5% instead of 1%?
  3. What is the standard deviation of the number of defective tablets in the sample?
  4. How does the binomial distribution behave when nn becomes very large and pp becomes very small?
  5. What are the implications of changing the acceptance criteria (e.g., accepting shipments with 2 defective tablets instead of 1)?

Tip: When calculating binomial probabilities, always use the binomial formula directly for small values of nn, but for large nn and small pp, consider using the Poisson approximation.

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Math Problem Analysis

Mathematical Concepts

Probability
Binomial Distribution

Formulas

P(X = k) = C(n, k) * p^k * (1 - p)^(n - k)
P(accept shipment) = P(X = 0) + P(X = 1)

Theorems

Binomial Theorem

Suitable Grade Level

Grades 10-12