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Do Now Natalie has a bag with 13 green, 4 red, 9 purple, and 6 yellow marbles . Express each probability as a percent. What is the probability that a marble chosen is red? What is the probability that a marble chosen is purple or green?
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Do Now Natalie has a bag with 13 green, 4 red, 9 purple, and 6 yellow marbles. Express each probability as a percent. What is the probability that a marble chosen is red? What is the probability that a marble chosen is purple or green? What is the probability that a marble chosen is blue? • A • B • C • D
Objective SWBAT find the theoretical and experimental probability of simple events.
What is probability? - used to measure the chance of an event happening - ratio that compares the number of favorable outcomes to the number of possible outcomes.
# of favorable outcomes # of possible outcomes P(event) =
All outcomes equally likely. All outcomes not equally likely.
1. Suppose a number cube is rolled. What is the probability of rolling an even number? There are 3 numbers on the number cube that are even: 2, 4, and 6. There are 6 possible outcomes: 1, 2, 3, 4, 5, and 6. P(even) = # of favorable outcomes # of possible outcomes Answer: The probability of rolling an even number is ½ or 50%
Express the probability as a fraction and a percent. • P(5) • P(less than 4) • P(2 or odd)
THEORETICAL PROBABILITY - what should occur in an experiment. 1. Suppose a number cube is rolled. What is the probability of rolling a 1? There is only one number 1 on the number cube. There are 6 possible outcomes: 1, 2, 3, 4, 5, and 6. P(one) = # of favorable outcomes # of possible outcomes Answer: The probability of rolling a is
EXPERIMENTAL PROBABILITY - what actually occurs when repeating a probability experiment many times. 1. Suppose a number cube is rolled. What is the experimentalprobability of rolling a 1? Answer: The experimental probability of rolling a one is P (greater than 4) =
Use a Sample to Make a Prediction Write down which of the following foods is your favorite. If the school was ordering food for 465 students, how many would be expected to eat hamburgers?
Make a Prediction SPORTS Miss Newman surveyed her class to see which sports they preferred watching. 44% preferred football, 28% basketball, 20% soccer, and 8% tennis. Out of 560 students in the entire school, how many would you expect to say they prefer watching basketball? Understand You know that 28% prefer basketball. You need to find how many students out of 560 prefer basketball. Plan Use the percent proportion to find 28% of 560.
part percent whole Make a Prediction Solve The percent is 28% and 560 is the whole. Let a represent the part.
Make a Prediction Answer: You can expect about 157 students to say they prefer watching basketball. CheckEstimate: 28% is about 25% 25% of 600 is 150. So, 157 is reasonable.
COLORS The students in an art class were surveyed about their favorite color. 32% preferred blue, 29% preferred red, 23% preferred yellow, and 16% preferred green. Out of 450 students in the entire school, how many would you expect to say they prefer red? • A • B • C • D A. about 6 B. 29 C. about 131 D. 144