Discrete Probability (Binomial)

Question 1

How many outcomes are there for each observation in the binomial setting?

Answer 1

There are two outcomes in the binomial setting, determined as “success” or “failure”. (example: either getting a job or not getting a job.)

Question 2

In the binomial setting, is the number of observations fixed or variable?

Answer 2

The number of observations is fixed in a binomial setting.

Question 3

Is it possible for past successes to influence future successes or failures in the binomial setting?

Answer 3

No, in the binomial setting, all of the trials are independent.

Question 4

Can the probability of success change for each observation?

Answer 4

No, the probability of success must be constant in each observation for the binomial setting.

Question 5

There’s a 30% chance that when Greg sees his grandmother, she will give him a quarter. If Greg sees his grandmother fifteen times, what are the chances that she won’t give him a quarter at least four times?

Answer 5

1-binomcdf(15, .7, 3) = .9999

There’s a 70% that she will not give him a quarter. Since the question is asking how many times won’t she give him a quarter, you have to find the probability of failure.