Key Terms
A listing of all the outcomes of an experiment and the probability associated with each outcome
Probability distribution
Population of a city
Discrete
With the following data, find the mean:
x P(x)
0 .2
1 .3
2 .4
3 .1
1.4
The amount of spread (or variation) in the data is described by the ____________ .
Variance
A variable measured or observed as the result of an experiment. By chance, the variable can have different values.
Random variable
Temperature in a rainforest
Continuous
A fair coin is tossed 4 times. What is the expected value for the number of heads?
2
The standard deviation of a probability distribution is 0.8. What is the variance of the probability distribution?
0.64
The mean of a probability distribution
Expected value
Amount of money it costs to buy a pumpkin
Discrete
The mean of a probability distribution is 1.3. What is the probability that x=1?
x P(x)
0 .3
1 ?
2 .4
3 .1
0.2
What are the computational steps for variance?
1. Subtract the mean from each value of x, and square
2. Multiply each squared difference by its probability
3. Sum the resulting products to arrive at the variance