As I mentioned on the first day of the semester, there are many online resources that you can consult to help you learn/review the material we cover in class.
Here is a full Khan Academy “Statistics and probability” course, which covers much of the same topics we will discuss this semester.
In particular:
- frequency tables and histograms are covered in the section titled “Displaying and comparing quantitative data” (as are stem-and-leaf plots, which come up in the extra credit exercises in “HW2-Graphs“),
- the “measures of central location” (mean and median) and quartiles are covered in the section “Summarizing quantitative data“
Try watching some of the Khan Academy videos to see if you find them useful.
Since the concepts (and calculations) of variance and standard deviation can be a bit tricky to understand, I recommend you watch the videos in the Khan Academy course on those topics:
“Variance and standard deviation of a population”:
https://www.khanacademy.org/math/statistics-probability/summarizing-quantitative-data#variance-standard-deviation-population
“Variance and standard deviation of a sample”
https://www.khanacademy.org/math/statistics-probability/summarizing-quantitative-data#variance-standard-deviation-sample
“More on standard deviation”
https://www.khanacademy.org/math/statistics-probability/summarizing-quantitative-data#more-on-standard-deviation