advertisement

Quiz #14a Answers August 1, 2014 Math 141 1. A class contains the following students as listed in the table. Let the random variable X denote the number of freshmen students selected in a sample of 6. class 7 freshmen 5 sophomores 12 Juniors Compute P (X = 2) = Answer: C(7, 2) ∗ C(17, 4) C(24, 6) 2. Classify the random variable as discreet or continuous. X = The number of cadets that can fit in a single elevator. discrete 3. Here is the probability distribution for a random variable X. X prob −4 10 0.2 17 0.1 25 0.15 36 0.30 (a) P (X = −4) = 0.25 (b) P (X > 17) = 0.15 + 0.30 = 0.45 4. draw the historgram for the probability distribution of therandom variable X. X prob 1 0.4 2 0.2 5 0.1 6 0.30 0.6 0.5 0.4 0.3 0.2 0.1 −1 1 2 3 4 5 6 7 8