1.1 RANDOM VARIABLES STATISTICS AND PROBABLITY G11
- 1. CHAPTER 1 Random Variables and Probability Distributions
- 3. In the study of basic probability, you have learned that for a certain experiment, there are various possible outcomes. *tossing a coin – head or tail
- 4. Random Variable Is a quantitative variable that is derived from the outcomes of a random experiment. *tossing a coin – number of times the coin turns up a tail *rolling 2 dice – the sum of the two numbers that face up *a spinner with blue, red, yellow and green spun in 20 times – number of times the spinner stops at color red
- 5. 2 types of Random Variables 1. Discrete random variable Is a random variable that can take only whole number values, outcomes that are countable. *finite number of possible outcomes 1. Continuous random variable Is a random variable that can take on non- integers as they take on values contained in an interval. *infinitely many possible outcomes, and is commonly used for measurements such as
- 6. EXAMPLE! Example 1: The number of children in a family. DISCRETE RANDOM VARIABLE Example 2: Ten children were asked to solve the Rubik’s cube. The time it took for them to complete the puzzle is summarized in the table below. Time (in min) < 1 1 – 2 2 – 3 > 3 Number of children 2 4 3 1
- 7. EXAMPLE! Example 3: Suppose that five cards are drawn from a deck, one at a time, without replacement. Let X = the number of times an ace is drawn from this experiment. What are the possible values of X? DISCRETE RANDOM VARIABLE
- 8. EXAMPLE! EXAMPLE 4: EverCharge is a company that manufactures batteries. They wish to record the number of defective batteries that are contained in each box before it is sent out for delivery. DISCRETE RANDOM VARIABLE EXAMPLE 5: Suppose EverCharge wants to check the average life span of their batteries. CONTINUOUS RANDOM VARIABLE
- 9. QUIZ
- 10. Identify whether the given experiment involves a discrete random variable or a continuous random variable. Write D if discrete and C if continuous. _______ 1. rotating a spinner 20 times that is equally divided into blue, green, red, and yellow sections and the number of times the spinner stops on the blue section. _______ 2. getting the distance traveled by a car. _______ 3. collecting data about the weights of students in a certain school. _______ 4. tossing a fair coin 5 times and number of heads is counted. _______ 5. picking a multiple of 4 less than 1,000,000 _______ 6. checking the monthly expenses of a small business _______ 7. recording the number of turnovers committed by a basketball team during the games in a season. _______ 8. tallying the number of gold medals won by the Philippines