Final answer:
The probability of having at most two watches needing repair within their warranty periods can be approximated using the Poisson distribution. The mean of the approximating Poisson distribution is 2. The probability of having at most two watches needing repair is approximately 0.676.
Step-by-step explanation:
The probability of having at most two watches needing repair within their warranty periods can be calculated using the binomial distribution. Let's define X as the number of watches that need repair. X follows a binomial distribution with n = 1,000 and p = 0.002 (probability of a watch needing repair). To approximate this distribution, we can use the Poisson distribution.
The mean of the approximating Poisson distribution is given by µ = n * p = 1,000 * 0.002 = 2. Therefore, we can approximate X using a Poisson distribution with a mean of 2.
To find the probability of having at most two watches needing repair, we can sum up the probabilities of X = 0, 1, and 2 using the Poisson distribution formula:
P(X ≤ 2) = P(X = 0) + P(X = 1) + P(X = 2)
Calculating this probability using the Poisson distribution, we find that P(X ≤ 2) ≈ 0.676