 # Secondary Catalogue

## Series: Discrete Random Variables

### Bernoulli Random Variables

A Bernoulli random variable is a special category of binomial random variables. Specifically, with a Bernoulli random variable, we have exactly one trial only (binomial random variables can have multiple trials), and we define “success” as a...Show More

### Binomial Random Variables

Remember that “bi” means two, so a binomial variable is a variable that can take on exactly two values. A coin is the most obvious example of a binomial variable because flipping a coin can only result in two values: heads or tails.

### Combinations of Random Variables

The combination of two random variables is the sum or difference of two variables. For instance, if I keep track of the time I spend walking each day, and separately keep track of the time I spend cycling each day, then I have two separate random...Show More

### Discrete Probability

A discrete random variable is a variable that can only take on discrete values. For example, if we flip a coin twice, we can only get heads zero times, one time, or two times. We can’t get heads 1.5 times, or 0.31 times. In this video we'll...Show More

### Geometric Random Variables

The difference is that for a geometric random variable, we’re looking at how many trials we have to use until we get a certain success. For a binomial random variable, we decided ahead of time on a certain number of trials. But for a geometric...Show More

### Permutations and Combinations

In order to answer many probability questions, we need to understand permutations and combinations. A permutation is the number of ways we can arrange a set of things, and the order matters. On the other hand, a combination is the number of ways...Show More

### Poisson Distributions

A Poisson process calculates the number of times an event occurs in a period of time, or in a particular area, or over some distance, or within any other kind of measurement, and the process has particular characteristics. In this video we'll...Show More

### Transforming Random Variables

In this video we'll look at how to transform a random variable by shifting or scaling it. Shifting a data set means that we add or subtract the same value from every point in the data set. Scaling a data set means that we multiply every point in...Show More

### “At Least” and “At Most,” and Mean, Variance, and Standard Deviation

For any binomial random variable, we can calculate the probability of at least some number of events occurring, or the probability of at most some number of events occurring. For instance, the probability of pulling at least 3 red marbles when we...Show More