Stat 21 Quiz _3 Key

# 30 iiipx05037 dcalculate iex 003 x 1 0 1 ex varx pxx

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Unformatted text preview: be speeding? False. This question is asking about geometric probability since it’s the probability that the first speeder will be the 401st car. Additionally, we don’t know probability and don’t know whether it’s the same for all cars. C) How many ways can 15 students be seated in a row of 4 desks so that there is always at least one empty desk between the students? False. This question is a combination and cannot be calculated with the binomial formula. Stat 21 Quiz #3 October 12, 2011 Name______________________________________________ Section # ___________________________________________ VERSION C 1. X is a random variable defined as: x ‐1 0 1 P(x) .4 .23 .37 A) Draw the cumulative distribution function (cdf) for X. B) Evaluate: i) P(X ≥ 1.8) = 0 ii) P(X ≤ ‐2.3) = 0 iii) P(X ≥ 0.5) = 0.37 D) Calculate: i) E(X) = -0.03 X ‐1 0 1 E(x) = Var(X) = P(X=x) 0.4 0.23 0.37 ‐0.03 0.7691 ii) Var(X) = 0.7691 x ‐ u ‐...
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