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The time that it takes for the next train to come follows a Uniform distribution with f(x) =1/40 where x goes between 1 and 41 minutes. Round answers to 4 decimal places when possible.

a. What type of distribution is this?
b. Is it a continuous or discrete distribution?
c. What is the mean of this distribution?
d. What is the standard deviation of this distribution?
e. Find the probability that the time will be at most 30 minutes.
f. Find the probability that the time will be between 9 and 16 minutes.
g. What is the 34th percentile of this distribution?
h. Find the probability that the time is more than 28 minutes given that it is at least 2 minutes.

User Gourneau
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Final answer:

The next train's waiting time is uniformly distributed from 1 to 41 minutes. It's a continuous distribution, with a mean of 21 minutes and a standard deviation of approximately 11.5470. Probabilities for specific time ranges were calculated, as well as the 34th percentile and a conditional probability.

Step-by-step explanation:

The time for the next train to come follows a Uniform distribution with density function f(x) = 1/40 for x between 1 and 41 minutes.

  1. The type of distribution is Uniform distribution.
  2. It is a continuous distribution.
  3. The mean of this distribution is the midpoint between 1 and 41 minutes, which is (1+41)/2 = 21 minutes.
  4. The standard deviation of this distribution is calculated using the formula σ = √((b-a)^2/12) which in this case is σ = √((41-1)^2/12) = √(1600/12) = √(133.3333) = 11.5470.
  5. The probability that the time will be at most 30 minutes is ∫ f(x) dx from x=1 to x=30 which gives (30-1)/40 = 0.7250.
  6. The probability that the time will be between 9 and 16 minutes is (16-9)/40 = 0.1750.
  7. The 34th percentile of this distribution is calculated by the formula x = a + P(b-a), where P is the percentile in decimal form; thus, x = 1 + 0.34(40) = 14.6 minutes.
  8. For the conditional probability that the time is more than 28 minutes given that it is at least 2 minutes, we use the formula P(A|B) = P(A and B) / P(B). Therefore, the probability is (41-28)/(41-2) = 13/39 = 0.3333.

User Jhauberg
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