Table of contents
- 1. Intro to Stats and Collecting Data24m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically53m
- 4. Probability1h 29m
- 5. Binomial Distribution & Discrete Random Variables1h 16m
- 6. Normal Distribution and Continuous Random Variables58m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 5m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
4. Probability
Complements
Problem 4.2.1
Textbook Question
Notation When randomly selecting a new smartphone, D denotes the event that it has a manufacturing defect. What do P(D) and P(D) represent?

1
Step 1: Understand the notation. In probability, 'P(D)' represents the probability of event 'D' occurring. Here, 'D' is the event that a randomly selected smartphone has a manufacturing defect.
Step 2: Clarify the meaning of 'P(D)'. It quantifies the likelihood of the event 'D' happening, expressed as a value between 0 and 1, where 0 means the event is impossible and 1 means the event is certain.
Step 3: Recognize that 'P(D)' is a mathematical representation of the probability. For example, if 5% of smartphones have defects, then P(D) = 0.05.
Step 4: If the problem also refers to 'P(D)', it is likely asking for the same probability value, as 'P(D)' is the standard notation for the probability of event 'D'.
Step 5: To calculate P(D) in practice, you would divide the number of defective smartphones by the total number of smartphones in the sample or population, using the formula: <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>P</mi><mo>(</mo><mi>D</mi><mo>)</mo><mo>=</mo><mfrac><mrow><mi>Number</mi><mo> </mo><mi>of</mi><mo> </mo><mi>defective</mi><mo> </mo><mi>smartphones</mi></mrow><mrow><mi>Total</mi><mo> </mo><mi>number</mi><mo> </mo><mi>of</mi><mo> </mo><mi>smartphones</mi></mrow></mfrac></mrow></math>.

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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, P(D) represents the probability that a randomly selected smartphone has a manufacturing defect. Understanding probability is essential for interpreting the likelihood of events in statistics.
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Introduction to Probability
Event
An event in probability is a specific outcome or a set of outcomes from a random experiment. In this case, D is the event that a smartphone has a manufacturing defect. Recognizing events helps in calculating probabilities and understanding the context of statistical analysis.
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Probability of Multiple Independent Events
Notation in Probability
Notation in probability provides a standardized way to represent events and their probabilities. P(D) specifically denotes the probability of event D occurring. Familiarity with this notation is crucial for effectively communicating and solving problems in statistics.
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Introduction to Probability
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