Basic Concepts
Probability can be expressed as a ....
Fraction, decimal, or percentage
A fair six-sided die is rolled. What is the probability of rolling a number greater than 3?
3/6 or 1/2.
What is theoretical probability?
a mathematical method for calculating the likelihood of an event occurring
What is experimental probability?
probability that is determined on the basis of the results of an experiment repeated many times
What is experiment mean?
is a test which we perform a number of trials or process that leads to an outcome
A coin is tossed three times. What is the probability of getting exactly two heads?
3/8
A bag contains 4 red balls, 6 blue balls, and 10 green balls. If a ball is drawn at random, what is the theoretical probability of drawing a red ball?
4/20 = 1/5
You toss a fair coin 50 times and record the outcomes. You get 30 heads and 20 tails. What is the experimental probability of getting heads?
Experimental probability of heads = (Number of heads) / (Total tosses) = 30/50 = 0.6 or 60%
What is an outcome?
The result of a single trial
A standard deck of 52 playing cards has 4 suits. What is the probability of drawing a heart?
13/52 = 1/4.
A spinner is divided into 8 equal sections numbered from 1 to 8. What is the probability of the spinner landing on an even number?
4/8 = 1/2
You have a bag containing 5 red, 3 blue, and 2 green marbles. You draw marbles at random, replacing them each time. After 100 draws, you get 45 red, 35 blue, and 20 green. What is the experimental probability of drawing a blue marble?
Experimental probability of drawing a blue marble = (Number of blue marbles drawn) / (Total draws) = 35/100 = 0.35 or 35%.
What is an event?
A set of outcomes
A bag contains 6 red, 2 blue, and 4 green marbles. What is the probability of randomly drawing a blue marble?
2/12 = 1/6
In a standard deck of 52 playing cards, what is the probability of drawing a queen?
4/52 = 1/13
You roll a six-sided die 60 times and record the results: 12 ones, 10 twos, 8 threes, 15 fours, 9 fives, and 6 sixes. What is the experimental probability of rolling a four?
Experimental probability of rolling a four = (Number of fours) / (Total rolls) = 15/60 = 0.25 or 25%.
What is the formula for probability?
P(E) = Number of favorable outcomes / Total number of outcomes
A family has three children. What is the probability that they have one boy and two girls?
3/8
In a class of 30 students, 18 students are boys and 12 are girls. If a student is chosen at random, what is the probability that the student is a girl?
12/30 = 2/5
In a survey of 200 people about their favorite type of music, the results were: 80 liked pop, 50 liked rock, 30 liked jazz, and 40 liked classical. What is the experimental probability that a randomly selected person from the survey prefers rock music?
Experimental probability of preferring rock = (Number of people who like rock) / (Total respondents) = 50/200 = 0.25 or 25%.