TOSS a Coin Toss a coin 50 times and record your results in a tally chart ht

Yesterdays Results Why were are results different?

Why were your results different? Example: Suppose we toss a coin 50 times and have 27 heads and 23 tails. We define a head as a success. The relative frequency of heads is: n/N = 27/50 = 54% We know the probability of a head is 50%. The difference between the relative frequency of 54% and the probability of 50% is due to small sample size.

Experimental Probability Learning Objective: To derive probabilities from experimental data Must use probability scale to describe the probability of events Should use numbers to describe the probability of an event happening Should use numbers to describe the probability of an event not happening

Theoretical Probability Previous lesson we calculated probability using equally likely outcome. A probability worked out this way is known as theoretical probability. Using words to define the outcome.

Experimental Probability Experimental Probability- is found by carrying out a series of experiments recording the results and using a frequency table. To find an experimental probability, the experiment has to be repeated several times. The rolling of dice each roll would be one TRIAL.

Experimental Probability Experimental Probability of an event= Number of times the event occurs Total number of trials

Example: A dice is thrown 50 times. The results of the 50 trials are shown in a frequency table. Score Frequency The experimental Probability of getting a 3= 3= 8 = The Experimental Probability of not getting a 3=

A regular dice is rolled. What is the probability of getting: a 4? ………… a) an even number? ………… b) a prime number? ………… c) a number greater than 4?………… A box contains 3 red sweets, 5 green sweets and 4 yellow sweets. A sweet is taken from the box. What is the probability of getting: a) a green sweet? ………… b) a yellow sweet? ………… c) a red or green sweet? ………… d) not a red sweet? ………… One card is taken from a pack of cards, what is the probability of picking out: a) a red card? ………… b) a club? ………… c) an ace? ………… d) not an ace? …………

Class Work Page 262 Read Working out Probabilities and take notes Exercise