Question

2) For each of the following stated probabilities, define an appropriate random variable, use mathematical notation to express the probability given, and state the outcomes of interest. DO NOT TRY TO COMPUTE THE PROBABILITY. Example: Question: Answer: The probability that sum of two dice rolls is less than 4. Let X = Sum of the rolls of two dice. P(X < 4). Outcomes of Interest: 2,3 Note: Each experiment below is a Discrete RV. a. The probability that there are more than 10 A's assigned in a class of 50 students. b. The probability there are at least five students in a class of 50 who receive above a 90 on the midterm.

Answer 1

a) The random variable here is

X = number of A's assigned in a class of 50

Required Probability is

P(X> 10)

Outcomes of interest are:

11.12.1350

b)

The random variable here is

X = number of students who score above 90 in a class of 50

Required Probability is

Plx>5)

Outcomes of interest are:

5,6,7,...,50