Ch 6 statistical distributions

Question 1

What is a random variable?

Answer 1

A random variable is an variable whose value depends on the outcome of a random event.

Question 2

What it another way to describe all the outcomes of an event?

Answer 2

A sample space.

Question 3

What is the difference between capital letters and lowercase for different variables.

Answer 3

Capital letters are used for the random variable.

Lowercase letters are used for the value the random variable takes.

Question 4

How to create a probability table?

what is unique about the p(X=x) row?

Answer 4

first row with small (x) and each value x can take.
second row with P(X=x) with the probability which is assigned to each of these.

P(X=X) row = 1

Question 5

How to create a probability mass function?

What is important to remember?

Answer 5

P(X=x)= the individual probabilities assigned and then the values of x which happen at those,

Have a zero and otherwise.

Question 6

What are the two conditions that must be met for binomial distribution?

Answer 6

• Fixed number of trials
• There are two possible outcomes
• The probability of success is the same each time
• The trials must be independent.

Question 7

What is the formula for the binomial distribution?

Answer 7

(n choose r) x probability of success^number of successes x probability of failure^number of failures.