Mathematics
Grade 4
15 min
Find probabilities using the binomial distribution
Find probabilities using the binomial distribution
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Introduction & Learning Objectives
Learning Objectives
Define probability as a fraction representing favorable outcomes out of total outcomes.
Describe a 'binomial' situation as one with two possible outcomes (e.g., success/failure).
Find a least common denominator for two fractions with unlike denominators.
Convert fractions into equivalent fractions with a common denominator.
Add two fractions with unlike denominators to find a combined probability.
Subtract two fractions with unlike denominators to compare probabilities.
Solve word problems that involve adding or subtracting fractional probabilities from simple binomial scenarios.
If you have a 1/2 chance of picking a red marble and a 1/3 chance of picking a blue one, how can we use fractions to compare your chances? 🔴🔵
Today, we are going o...
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Key Concepts & Vocabulary
TermDefinitionExample
ProbabilityThe chance of something happening, written as a fraction. The top number (numerator) is the number of ways it can happen, and the bottom number (denominator) is the total number of possible outcomes.The probability of a coin landing on heads is 1/2, because there is 1 head and 2 total sides (heads and tails).
Binomial DistributionA special name for any situation where there are only TWO possible outcomes. Think 'bi' like in 'bicycle' (two wheels). The outcomes could be win/lose, yes/no, or heads/tails.Flipping a coin is a binomial event because the only outcomes are heads or tails.
Unlike DenominatorsWhen the bottom numbers of two fractions are different. You can't add or subtract them until you make the denominators the same.The f...
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Core Formulas
Combined Probability Rule (Addition)
P(\text{A or B}) = P(A) + P(B)
To find the combined chance of two separate events happening, we add their probabilities together. You MUST find a common denominator before you can add the fractions.
Probability Difference Rule (Subtraction)
P(\text{Difference}) = P(\text{Larger}) - P(\text{Smaller})
To find out how much more likely one event is than another, we subtract the smaller probability from the larger one. You MUST find a common denominator before you can subtract.
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Challenging
The combined probability of getting a red OR a blue gumball is 11/12. If the probability of getting a red gumball is 1/4, what is the probability of getting a blue gumball?
A.10/8
B.8/12
C.14/12
D.12/16
Challenging
There are three buttons: Red, Green, and Blue. The probability of a light turning on is 1/2 for Red, 1/8 for Green, and 1/4 for Blue. What is the combined probability that a light will turn on if you press any one of them?
A.3/14
B.7/8
C.3/8
D.6/8
Challenging
Team A wins 2 out of every 5 games, so their probability of winning is 2/5. Team B wins 1 out of every 3 games, so their probability is 1/3. How much greater is Team A's probability of winning than Team B's?
A.1/2
B.3/8
C.1/15
D.11/15
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