Module 3-2 Flashcards
What are the 2 types of Random Variables?
Categorical and Quantitative
What are the two types of Quantitative variables?
Discrete and Continuous
What are Discrete Random Variables?
Variables that can take one of a finite number of distinct outcomes ex. Number of stores in a mall, number of cars
What are Continuous Random Variables?
Variables that can take any numeric value within an interval of values ex. Cost of books this term, height of hockey players
What is a Probability Model for Discrete Random Variables?
The collection of all possible values of a random variable and the probabilities that the values occur
What are the rules of Discrete Probability distributions?
All probabilities must add to one and a single,e probability must be less than 1
What is the Expected values or E(X) or the population mean?
This is the value that you would expect to observe on average if the experiment is repeated over and over again. It is the center of distribution
How do you find the expected value of discrete random variables?
You multiply the variable by the probability of getting it add it to all the others
How is the variance for discrete random variables found?
Square the difference between the X value and the expected value and multiply the square by the probability of the X value and add those all up
How can the standard deviation of a Discrete Random Variable be found?
By taking the square root of the variance
How does shifting the values of the variable affect things?
Shifting changes the mean but does not change the variance and standard deviation
How does scaling affect the stuff related to discrete random variables?
Scaling multiplies the mean by the number
Scaling changes the variance by the square of the constant
Scaling changes the st.dev by multiplying the value by the new st.dev
How is the sum of two discrete random variables found?
By adding them
How is the sum of the variance of two discrete random variables found?
By adding the different variances (never subtract them)
