1. Key statistical concepts.
Measures of centre and variability.

2. Presumed (prior) knowledge.

7. Example 1
It is a continuous data; we can use class intervals of length 1 cm.
Enter data into a new spreadsheet on your GDC to draw a histogram and get all statistics. Use midpoint of each class interval.
The modal class is
as this occurred most frequently.

8. Ctrl Menu 3: Add X Variable with Summary List.
The data is positively skewed.

9. Draw a box plot now.
No outliers, hover over the boxplot to see Q1, Q3, min and max values.

10. Other one-variable statistics can be obtained either in the spreadsheet or in the calculator screen.
Mean = 5.3
Standard deviation 1.21
IQR=Q3-Q1= =2

14. For data which is not symmetric.
In our example:
The median is pulled towards the tail (in the direction of skewness).

16. When data is grouped in classes, we use the midpoint and then we can only estimate the mean as we do not have the data points listed.