Published

September 4, 2025

Math 141: Readings for September 4, 2025

Reading

Before coming to lecture today, please read the following material:

  • OI Section 4.1

Homework Assignment

After you’ve completed the reading, but before coming to class, please complete the following homework assignment. Bring your responses to this assignment (handwritten or typed) to class on a piece of paper:

  • OI Exercises: 4.2, 4.4, 4.6 (note: use R when needed!)

  • Suppose you believe 40% of Portlanders think the city should install more bike lanes. You will take a simple random survey of 50 Portlanders to test your belief.

    1. Assume your belief is true. Let \(X\) be the number of survey respondents who think the city should install more bike lanes. Does \(X\) follow a Binomial distribution? If so, what are \(n\) and \(p\)?

    2. Calculate the expected value and standard deviation of \(X\) (still assuming your belief is true)

    3. Suppose you conducted the survey and found 30 respondents wanted more bike lanes. What’s the probability that \(X\geq 30\)? (use R!)

    4. Draw the connection between the probability you calculated and a hypothesis test.