Stats - Statistical Distributions

2021-01-26
2 min read

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Flashcards

What is a random variable??

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

What is the notation for a random variable??

Capital letters, $X$.

What is the notation for the random variable $X$ taking a particular value $x$??

$$ P(X = x) $$

Can you explain $P(X = x)

The probability that the outcome of the random variable $X$ was the specific outcome $x$.

What’s the shorthand for $P(X = heads)$??

$$ p(heads) $$

What is a discrete uniform distribution??

A distribution that can only take specific values, which all have the same probability for each outcome.

What is a piecewise function??

We choose the function from a list depending on the input.

PHOTO PROBABILITY FUNCTION What is $P(X = 2)$??

$$ 0.2 $$

PHOTO PROBABILITY TABLE What is $P(X = 3)$??

$$ 0.3 $$

What is the advantage of writing probability distributions as a function??

You can have a rule or expression based on the outcome.

What is the advantageo f writing probability distributions as a table??

It’s easier to see the probability for each outcome.

What is the underlying sample space for $X$, the number of heads when three coins are tossed??

$$ HHH, HHT, HTT, HTH, THH, THT, TTH, TTT $$

What was the head of the table be for the probability distribution of $X$, the number of heads when three coins are tossed??

Number of heads, $x$.

In a probability distribution table where all possible outcomes are listed, what must the sum of all probabilities equal??

$$ 1 $$

What would that notation for “the sum of all probabilities”??

$$ \sum p(x) $$

PHOTO PROBABILITY TABLE RANGE What is $P(X > 3)$??

$$ 0.6 $$

For a discrete random variable, what is $p(x)$ called??

The probability mass function.

Why is $p(x)$ called a probability mass function for a discrete random variable??

Because the probability of each outcome represents an actual amount of the overall probability.

Visualise what the graphical probability distribution would look like for a six-sided die??

PHOTO GRAPHICAL PROBABILITY DISTRIBUTION


Metadata
date: 2021-01-26 09:00
tags:
- '@?stats'
- '@?probability'
- '@?distributions'
- '@?year-1'
- '@?public'
- '@?school'
title: Stats - Statistical Distributions
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