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
4. Probability
Basic Concepts of Probability
Problem 4.1.6
Textbook Question
Penicillin “Who discovered penicillin: Marcel Bich, William Penn, Jonas Salk, Alexander Fleming, or Louis Pasteur?” If you make a random guess for the answer to that question, what is the probability that your answer is the correct answer of Alexander Fleming?

1
Step 1: Identify the total number of possible answers provided in the question. In this case, there are 5 options: Marcel Bich, William Penn, Jonas Salk, Alexander Fleming, and Louis Pasteur.
Step 2: Recognize that the question asks for the probability of randomly guessing the correct answer, which is Alexander Fleming.
Step 3: Recall the formula for probability: \( P(A) = \frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}} \).
Step 4: Determine the number of favorable outcomes. Since there is only one correct answer (Alexander Fleming), the number of favorable outcomes is 1.
Step 5: Substitute the values into the probability formula: \( P(A) = \frac{1}{5} \). This represents the probability of randomly guessing the correct answer.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Probability
Probability is a measure of the likelihood that a particular event will occur, expressed as a number between 0 and 1. In this context, it quantifies the chance of randomly selecting the correct answer from a set of options. If there are five possible answers, the probability of guessing correctly is 1 out of 5, or 0.2.
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Random Guessing
Random guessing refers to making a choice without any prior knowledge or reasoning. In the context of the question, it implies selecting one of the five names without any information about who actually discovered penicillin. This method of selection assumes that each option has an equal chance of being chosen.
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Sample Space
The sample space is the set of all possible outcomes in a probability experiment. For this question, the sample space consists of the five names provided: Marcel Bich, William Penn, Jonas Salk, Alexander Fleming, and Louis Pasteur. Understanding the sample space is crucial for calculating the probability of selecting the correct answer.
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