I spent about 15 minutes going over homework from 1.2, then gave a quiz on sections 1.1 and 1.2, so I had about 15 minutes for the 1.3 lesson. I only went over the five-number summary using the very top of the worksheet here. I assigned questions 1 and 2 for homework since they did not include box plots.
I’ve found that circling the median (and min and max) makes finding quartile one and three more difficult. It is easier to draw a vertical line through or between two numbers. When circling the minimum (or max) some students don’t use those numbers to find Q1. And when circling two numbers for the median, the students don’t use them to calculate Q1.
I passed out the quizzes from the previous day but because the grades were quite high, I did not spend time going over them. I did put a dot plot and a box and whisker plot of the grades up on the screen for the students to see.
I then went over questions 1 and 2 from the previous night’s homework.
Next, I almost finished doing the rest of the notes worksheet that I had passed out the day earlier. I spent a great deal of time explaining:
- where “quartiles” come from, showing them visually that the list of numbers is being cut into four equal sections.
- that each of the four sections of the box and whisker plot represent a quarter of the data in the list, and that “compact” parts mean that the data has little variance
- that it is easy to compare two different populations when using stacked box plots
- the IQR is like the range. The range is the difference between the max and min, the IQR is the difference between the first and third quartiles. I made note of this using brackets on my five-number summaries.
- the IQR shows up on the box-plot and the width of the box
I did not finish the last part – taking Michael Jordan out of the list of players and redoing the box plot for the 97 Bulls so I left that to them to do for homework.
They worked on numbers 3 – 5, 8, 10, and 11
Question 8 has the students make two box plots using the same scale but many accidentally draw two separate scales. When going over this homework, I will demonstrate why it is difficult to compare two populations using different scales using the following. It is downloadable as well, although Fathom files cannot be uploaded on WordPress :-(