Appex 08

STA 112 - Fall 2022

Part 1

  1. Create a new project from this template in RStudio Pro:
https://github.com/sta-112-f22/appex-08.git
  1. Replace the text in the top code chunk that says INSERT YOUR GOOGLE SPREADSHEET URL HERE with the Google Spreadsheet URL with your magnolia data.
  2. Fit an intercept only model to calculate the average leaf length in your sample
  3. Use the summary function on the linear model you fit
  4. What is the standard error for the mean length? Interpret this value.

Part 2

  1. Open appex-08.qmd
  2. Calculate the \(t^*\) value for your confidence interval
  3. Calculate the confidence interval “by hand” using the \(t^*\) value from exercise 2 and the mean and standard error from the previous application exercise
  4. Calculate the confidence interval using the confint function
  5. Interpret this value

Part 3

  1. Open appex-08.qmd
  2. Fit the model of leaf_width and leaf_length in your data
  3. Calculate a confidence interval for the estimate \(\hat\beta_1\)
  4. Interpret this value

Part 4

  1. Open appex-08.qmd
  2. Examine the summary of the model of leaf_length and leaf_width with your data
  3. Test the null hypothesis that there is no relationship between the length and width of magnolia leaves
  4. What is the p-value? What is the result of your hypothesis test?