Worksheet 6: Random Variables / The Binomial Distribution

Random Variables

Q1: For the random variable with the given discrete probability distribution, find the following. Show your work to get credit.

X	0	1	2	3	4
P(X)	0.45	0.05	0.10	0.25	0.15

(a) Mean

(b) Standard deviation

(c) P(2)

(d) P(0 or 3)

(e) P(less than or equal 2)

(f) P(greater that 0)

The Binomial Distribution

Q2: About 37% of students say that math is their most difficult subject. Suppose 16 students (n = 16) are randomly selected. Show your work to get credit.

(a) Find P(10), which is the probability that exactly 10 students in the sample say that math is their most difficult subject. Round answer to 3 decimal places.

(b) Find P(greater than 9), which is the probability that more than 9 students in the sample say that math is their most difficult subject. (Hint: It is more efficient to use binomcdf( ) TI-83/84 function.) Round answer to 3 decimal places.

(c) Mean. (Round to 2 decimal places.)

(d) Standard deviation. (Round to 2 decimal place)