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
Addition Rule
Problem 3.3.23c
Textbook Question
23. Engineering Degrees The table shows the numbers of male and female students in the U.S. who received B.S. degrees in engineering in a recent year. A student earning a B.S. degree in engineering during that year is selected at random. Find the probability of each event.
(Source: National Center for Educational Statistics)

c. The student is not female or did not receive a mechanical engineering degree.

1
Step 1: Understand the problem. We are tasked with finding the probability that a randomly selected student is not female or did not receive a mechanical engineering degree. This involves using the complement rule and the addition rule in probability.
Step 2: Identify the total number of students. From the table, the total number of students who received B.S. degrees in engineering is 121,956.
Step 3: Calculate the number of students who are female and received a mechanical engineering degree. From the table, the number of females who received mechanical engineering degrees is 5,032.
Step 4: Use the complement rule to find the number of students who are not female or did not receive a mechanical engineering degree. This is equivalent to subtracting the number of students who are female and received a mechanical engineering degree from the total number of students.
Step 5: Divide the result from Step 4 by the total number of students (121,956) to find the probability. This gives the probability that a randomly selected student is not female or did not receive a mechanical engineering degree.

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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 an event will occur, expressed as a number between 0 and 1. In this context, it involves calculating the chance of selecting a student who is either not female or did not receive a mechanical engineering degree. This requires understanding how to combine probabilities of different events.
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Complementary Events
Complementary events are pairs of outcomes in a probability scenario where one event occurs if and only if the other does not. In this case, the event of selecting a student who is not female or did not receive a mechanical engineering degree can be analyzed by considering the complementary event: selecting a female student who received a mechanical engineering degree.
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Complementary Events
Joint Probability
Joint probability refers to the probability of two events occurring simultaneously. To solve the question, one must calculate the joint probability of selecting a female student who received a mechanical engineering degree and then use this to find the probability of the complementary event. This involves using the data from the table to determine the relevant counts.
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