Unit 9 Review

A ​ (a)   is a variable which represents the outcome of a randomized trial or event. A random variable can take any value within a pre-determined range and is different for each trial.

• A ​ (b)   has a finite or countable set of possible values. For any two consecutive possible values, there is a minimum distance over which the random variable cannot be equal to anything in between.

• This contrasts from a ​ (c)   , which can take an infinite and uncountable set of possible values.

• There is a common perception that discrete values must be natural numbers. However, this is not true. In certain contexts, ​ (d)   .

• Discrete values can be decimals or negative
• continuous random variable
• discrete random variable
• Random Variable

Which of the following random variables are discrete?

Groups:

(a) Discrete Variables

,

(b) Non-Discrete Variables

• Practices held before championship

• Distance run on a track

• Width of each lane on the track

• Height of each hurdle

• Participants from each school in track championship

• Average speed of all runners

• Time it takes to run a lap

• Hurdles cleared in one lap

Tara goes swimming 80% of the time in the summer. Let X = the number of days Tara swims in a 4-day period. What is the probability distribution of X=2?

A ​ (a)   of a discrete random variable lists all possible outcomes for a trial and their respective probabilities. The distribution must include probabilities that:

• Are between ​ (b)   (inclusive).

• Sum to exactly ​ (c)   .

• To create a probability distribution for a discrete random variable, calculate the probability of each possible value.

This may include listing ​ (d)   of certain events, ​ (e)   of specific successes/failures, accounting for multiple ways to get identical results, and/or applying contextual information.

• 0 and 1
• 1
• probability distribution
• all possible combinations
• multiplying probabilities
• 0 and 0.5
• 0 and 2
• 1 and 2

A ​ (a)   is a bar chart representing the probability of each possible value of a discrete random variable.

• probability distribution graph
• frequency distribution chart
• bell curve chart

P(X=0)

P(X=1)

P(X=2)

P(X=3)

P(X=4)