Table of contents
- 1. Introduction to Statistics53m
- 2. Describing Data with Tables and Graphs2h 1m
- 3. Describing Data Numerically1h 48m
- 4. Probability2h 26m
- 5. Binomial Distribution & Discrete Random Variables2h 55m
- 6. Normal Distribution & Continuous Random Variables1h 48m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 17m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 20m
- 9. Hypothesis Testing for One Sample1h 8m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 30m
- 14. ANOVA1h 4m
5. Binomial Distribution & Discrete Random Variables
Discrete Random Variables
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
A factory produces lightbulbs in batches of 50. The probability distribution for the number of defective lightbulbs in a randomly selected batch is shown below. Find the expected value.

A
0.17
B
1.7
C
0.03
D
2.5

1
Understand the concept of expected value in probability distributions. The expected value is a measure of the center of the distribution, often referred to as the mean of the distribution.
Identify the random variable X, which represents the number of defective bulbs in a batch. The possible values of X are 0, 1, 2, 3, 4, and 5.
Recognize the probability distribution P(X) associated with each value of X. These probabilities are given as 0.20, 0.30, 0.25, 0.15, 0.07, and 0.03 respectively.
Use the formula for expected value: E(X) = Σ [x * P(x)], where x is a value of the random variable and P(x) is the probability of x occurring.
Calculate the expected value by multiplying each value of X by its corresponding probability and summing these products: E(X) = (0 * 0.20) + (1 * 0.30) + (2 * 0.25) + (3 * 0.15) + (4 * 0.07) + (5 * 0.03).
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