Probability
What two values is a probability between?
0 and 1
What are 2 things do you need to approximate independence?
Random sample AND n<10% of population
The height (inches) of a Cal Poly student is an example of what kind of random variable?
Continuous
How many outcomes does a binomial/geometric distribution have?
2 (Success/Failure)
How would you write the probability of A given B?
P (A | B)
What is P(S), the probability of the set of all possible outcomes in the sample space?
P(S) = 1
If there is an infinite population, what other condition needs to be met to assume independence?
The number of sales out of 3 telemarketing calls is an example of what kind of random variable?
Discrete
How many observational units are in a binomial/geometric distribution?
1
What's the formula for P(A | B)
P(A | B) = P(A and B)/P(B)
If P(A) = 1, and P(A) = P(B) + P(C), according to the compliment rule, how do you find P(B)?
P(B) = 1 - P(C)
A telemarketer makes 3 randomly sampled calls. Are the outcomes (sale or no sale from call) independent? If so, why?
Yes, because we can assume that 3 calls are less than 10% of all calls made, and the sample is random.
Are random variables quantitative or categorical?
Quantitative
X = # of successes out of n attempts for which distribution?
Binomial distribution
How would you write the probability of using red paint, given that you just used blue paint.
P(red | blue)
What is the Multiplication Rule if A and B are independent?
P(A and B) = P(A) x P(B)
Is the employment status of customers waiting in line at the post office independent?
Yes
What kind of random variable is the color of an M&M randomly selected from a bag?
This is NOT an example of a random variable.
X = # of attempts before 1st success for which distribution?
Geometric distribution
If the probability of getting an A on the midterm AND an A on the final is .65, and the probability of getting an A on the final is .85, what is the probability of getting an A on the final IF you got an A on the midterm?
P(A on final | A on midterm) = .76
In a residential area in your country, 35% of households have Netflix accounts. What is the probability that household A has a Netflix account?
P(A) = .35
Are the successive measurements of your heart rate as you exercise on a treadmill independent?
No
A company’s employee database includes data on whether or not the employee includes a dependent child in his or her health insurance. Is this variable discrete or continuous?
Discrete
6% of residents do not have access to the internet. We randomly select n = 3 residents. We want to know the probability exactly 1 does not have access to the internet. Let the random variable X = number of residents in the sample of 3 that do not have access to the internet. Is this a binomial or geometric distribution?
Binomial
If the probability of dropping your phone is .78, and the probability of dropping your phone and breaking it is .67, what is the probability of breaking your phone IF you drop it.
P (break | drop) = P(break and drop)/P(drop) = .86