In your own words, provide an interpretation of the mean (or expected value) of a discrete random variable.
Table of contents
- 1. Intro to Stats and Collecting Data1h 14m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically2h 5m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables3h 6m
- 6. Normal Distribution and Continuous Random Variables2h 11m
- 7. Sampling Distributions & Confidence Intervals: Mean3h 23m
- Sampling Distribution of the Sample Mean and Central Limit Theorem19m
- Distribution of Sample Mean - Excel23m
- Introduction to Confidence Intervals15m
- Confidence Intervals for Population Mean1h 18m
- Determining the Minimum Sample Size Required12m
- Finding Probabilities and T Critical Values - Excel28m
- Confidence Intervals for Population Means - Excel25m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 25m
- 9. Hypothesis Testing for One Sample3h 29m
- 10. Hypothesis Testing for Two Samples4h 50m
- Two Proportions1h 13m
- Two Proportions Hypothesis Test - Excel28m
- Two Means - Unknown, Unequal Variance1h 3m
- Two Means - Unknown Variances Hypothesis Test - Excel12m
- Two Means - Unknown, Equal Variance15m
- Two Means - Unknown, Equal Variances Hypothesis Test - Excel9m
- Two Means - Known Variance12m
- Two Means - Sigma Known Hypothesis Test - Excel21m
- Two Means - Matched Pairs (Dependent Samples)42m
- Matched Pairs Hypothesis Test - Excel12m
- 11. Correlation1h 24m
- 12. Regression1h 50m
- 13. Chi-Square Tests & Goodness of Fit2h 21m
- 14. ANOVA1h 57m
5. Binomial Distribution & Discrete Random Variables
Discrete Random Variables
Problem 6.1.17a
Textbook Question
[NW] [DATA] TelevisionsIn the Sullivan Statistics Survey I, individuals were asked to disclose the number of televisions in their household. In the following probability distribution, the random variable X represents the number of televisions in households.
a. Confirm that this represents a discrete probability distribution.

Verified step by step guidance1
Step 1: Verify that the random variable X is discrete by checking if it takes on countable values. Here, X represents the number of televisions, which are whole numbers from 0 to 9, so X is discrete.
Step 2: Check that each probability value P(x) is between 0 and 1 inclusive. Review the given probabilities: 0, 0.161, 0.261, 0.176, 0.186, 0.116, 0.055, 0.025, 0.010, and 0.010. All these values satisfy 0 \leq P(x) \leq 1.
Step 3: Confirm that the sum of all probabilities equals 1. Calculate the sum using the formula: \(\sum_{x=0}^{9} P(x) = 0 + 0.161 + 0.261 + 0.176 + 0.186 + 0.116 + 0.055 + 0.025 + 0.010 + 0.010\).
Step 4: If the sum from Step 3 equals 1, then the set of probabilities forms a valid probability distribution for the discrete random variable X.
Step 5: Conclude that since X is discrete, all probabilities are between 0 and 1, and their sum is 1, this table represents a discrete probability distribution.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Discrete Probability Distribution
A discrete probability distribution lists all possible values of a discrete random variable and their associated probabilities. Each probability must be between 0 and 1, and the sum of all probabilities must equal 1. This ensures the distribution accurately represents the likelihood of each outcome.
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Variance & Standard Deviation of Discrete Random Variables
Random Variable
A random variable is a numerical outcome of a random phenomenon. In this case, X represents the number of televisions in a household, which can only take integer values. Understanding the random variable helps in interpreting the probability distribution and analyzing the data.
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Probability Sum Rule
The probability sum rule states that the total probability of all possible outcomes must be exactly 1. This rule is essential to confirm that a given set of probabilities forms a valid probability distribution, ensuring that all possible events are accounted for.
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