Discrete random variable

  • A discrete random variable is a variable that has a fixed amount of possible numbers. examples: shoe size ( you can be an 8 or an 8.5 but not an 8.34) or AP score.

Expected value

  • Mean

Standard deviation 2.22 Interpret: The wages typically vary by

Ms williamson would rather assign wages so that employees could get any amount from 10 - 20 $ and all are equally likely. This means that we are no longer dealing with discreet variables they are now continuous.

Check Your Understanding!

Home alone is a series of American Christmas family comedy films created by John Hughes. There are 5 Home Alone movies. Below is a probability distribution of the number of Home Alone movies wacthed by a very large sample of high school students

Number of home alone movies watched012345
Probability0.150.420.32?0.020.01

a. Write the event the student has seen 3 home alone movies using prbability notation. Then find this probability

P(X=3) = 0.08

Explain in words what P(x>=3) means. What is this probability?

The probability of you having watched 3 or more home alone movies P (X>=3) = 0.08+0.02+0.01 = 0.011

Caclulate and interprest the expected value of X