HW05: Confidence Interval for a Single Mean

Due date: 2022-10-24

Use the dataset elmhurst. Download the data and save the CSV file into your HW05 directory (so that it is submit when you upload your HW05 folder).

elmhurst <- read.csv("elmhurst.csv")
## if this didn't work,
## then your data and your .qmd file for HW05
## are in different folders.
## Put both files in your HW05 folder.

Read the help file about elmhurst, to better understand the data set.

Please submit a folder containing your Quarto input (qmd) and output (html) documents for this lab, named HW05, to our shared Google Drive folder when you are finished.

  1. Pick a numeric variable of your choice and use it for the rest of this assignment. No code needed here.

  2. Make a histogram of your numeric variable and describe its shape.

  3. Explain, in the context of these data, why the shape might make sense.

  4. Calculate a 98% confidence interval of your numeric variable.

  5. Interpret in context of the data your confidence interval. Don’t forget the units (they’re hopefully listed in the help flie).

  6. If you were to make a 90% confidence interval, would it be wider or narrower than your 95% interval above? Why?

  7. If you were to collect fewer data, say half as much data, and make a 95% confidence interval, would it be wider or narrower than your 95% confidence interval above? Why? Try to use new keywords to describe why.