Name__________________________________________ Math _______________
Probability Day 3 Practice – Theoretical Probability
1) Write each of the following definitions in your own words.
Theoretical –
Theoretical probability –
P(event) =
2) At a school fair, you have a choice of randomly picking a ball from Basket A or Basket B.
Basket A has 5 green balls, 3 red balls, and 8 yellow balls. Basket B has 7 green balls, 4 red
balls, and 9 yellow balls. You can win an iPhone if you pick a red ball.
A) Complete the chart. Write each answer in simplest form.
Basket
A
Basket
B
Total Number of Outcomes
Number of Red Balls
P(win) =
B) Which basket should you choose if you want the better chance of winning?
3) Bobby has 4 nickels, 6 pennies, 4 dimes and 2 quarters in his pocket. He picks a coin at
random. What is the probability that he will pick a nickel or a dime? Write your answer as a
fraction, as a decimal, and as a percent.
4) A class has 18 boys and 14 girls. The teacher randomly picks one child to lead the class in
math facts.
A) What is the probability that the teacher picks a boy?
B) What is the complement of the event in letter A?
C) What is the probability of the complement?
D) Describe two different ways you could find the answer to part C.
Use the spinner for 5−8.
5) In 100 spins, about how often can you expect to land on a number evenly divisible by 2?
6) In 50 spins, about how often can you expect to land on a number less than 4?
7) In 150 spins, about how often can you expect to land on an 8?
8) Error Analysis Sam says there is a greater chance of landing on an even number than on
an odd number. What is his error?