click below
click below
Normal Size Small Size show me how
Probability Dist.
4.1
Question | Answer |
---|---|
What is random variable x | numerical value associated with each outcome of a probability experiment |
what is a discrete variable? | finite or countable # of outcomes |
what is a continuous variable? | uncountable # of outcomes, represented by an interval on a number line. Example: Age, Height, Weight |
what are the discrete probability distribution conditions? | 0 < or = to P(x) < or = to 1 SUM P(x)=1 |
What are the 2 steps in constructing a discrete probability distribution ? | 1. make freq. dist. for possible outcomes 2. SUM F 3. find probability of each outcome [P(f)] by F/(SUM F) 4. Check work. All add up to 1? |
what is the formula to find the mean of the discrete random variable | u=E[x*P(x)] |
what is the formula to find the variance of a discrete random variable? | o^2=E[(x-u)^2P(x)] |
what is the formula to find the standard deviation of a discrete random variable? | o=sq rt o^2 =sq rt E[(x-u)^2P(x)] |
What is the formula to find the expected value of a discrete random variable? | E(x)=u=E[x*P(x)] |
At a raffle, 1,500 tickets are sold at $2 each for 4 prizes of $500, $250, $150, & $75. You buy one ticket. What is the expected value of your gain? | -$1.35: Because the expected value is neg, you can expect to lose an average of $1.35 for each ticket you buy. |