Vocabulary
define random variable
random variable is a variable whose possible values are determined by chance.
discrete or continuous?
X= The number of socks getting lost in the washing machine every week
DISCRETE
what is the probability of getting tails on a coin toss?
1/2 or 50%
0.85
.3023
define expected value
average gain or loss if the procedure is repeated
Discrete or Continuous?
X = The height of every student in grade 11
CONTINUOUS
what's the probability of getting black face cards in a deck
3/26 or 11.5%
.1141
0.29
define discrete random variable
discrete random variables are countable distinct values that when combined will have a sum of 1
which is not a discrete random variable?
a.) X = The volume of water in a cup of coffee
b.) X = The number cellphones in a store
c.) X = The amount of floors in a skyscraper
A.
what is the probability of rolling doubles with two six-sided dice?
1/6 or 16.7%
.4969
2.74
Normal distribution is also known as?
Gaussian distribution
DISCRETE OR NOT?
X | 1 | 2 | 3 | 4 | 5 |
P(X) | 0.10 | 0.20 | 0.25 | 0.40 | 0.05 |
DISCRETE (Σ = 1)
probability of rolling a 3 or 8 with two six-sided dice
7/36 or 19.4%
.3997
1.28
define normal distribution
normal distribution is a probability distribution that is symmetric about the mean, and is graphed using the bell curve.
DISCRETE OR NOT
X | 0 | 1 | 2 | 3 | 4 |
P(X) | 1/10 | 3/10 | 1/5 | 1/4 | 3/10 |
NOT DISCRETE (Σ = 1.15)
A pouch has 8 red marbles, 10 blue marbles and 7 yellow marbles. What has a greater probability, getting blue marbles, or getting either a red or yellow marble?
Getting a red or yellow [3/5 or 60%]
.4099
1.34