Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
5. Binomial Distribution & Discrete Random Variables
Discrete Random Variables
Problem 4.T.3a
Textbook Question
Determine whether the distribution is a probability distribution. If it is not a probability distribution, explain why.


1
Step 1: Recall the conditions for a probability distribution. A probability distribution must satisfy two criteria: (1) Each probability value, p(x), must be between 0 and 1 inclusive, and (2) The sum of all probability values must equal 1.
Step 2: Check the first condition. Inspect each value of p(x) in the table to ensure that all values are between 0 and 1 inclusive. Specifically, verify that 0 ≤ p(x) ≤ 1 for each value.
Step 3: Check the second condition. Add all the values of p(x) from the table: 0.03 + 0.09 + 0.19 + 0.32 + 0.37. Ensure that the sum equals 1.
Step 4: If any p(x) value is outside the range [0, 1], or if the sum of p(x) values does not equal 1, then the distribution is not a probability distribution. Identify and explain the specific issue.
Step 5: If both conditions are satisfied, conclude that the given distribution is a valid probability distribution.

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
3mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Probability Distribution
A probability distribution describes how the probabilities are distributed over the values of a random variable. For a discrete random variable, it assigns a probability to each possible value, ensuring that the sum of all probabilities equals 1. This concept is fundamental in determining whether a given set of probabilities constitutes a valid probability distribution.
Recommended video:
Guided course
Calculating Probabilities in a Binomial Distribution
Properties of Probability
The properties of probability state that each probability must be between 0 and 1, inclusive, and the total probability of all outcomes must sum to 1. If any probability is negative or if the total does not equal 1, the distribution is invalid. Understanding these properties is essential for evaluating whether the provided probabilities form a legitimate probability distribution.
Recommended video:
Introduction to Probability
Discrete Random Variables
Discrete random variables are those that can take on a countable number of distinct values, often represented in a table format. Each value has an associated probability, and the analysis of these variables often involves checking the validity of their probability distributions. Recognizing the nature of discrete random variables is crucial for interpreting the data presented in the question.
Recommended video:
Guided course
Variance & Standard Deviation of Discrete Random Variables
Watch next
Master Intro to Random Variables & Probability Distributions with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice