Statistics Examples

$8$ , $9$ , $0$ , $7$ , $8$ , $9$ , $6$ , $7$ , $0$ , $3$ , $4$

Step 1

The class width can be found by finding the difference of the maximum data value and the minimum data value (range of data) divided by the number of classes.

$\frac{(Maximum Data Value - Minimum Data Value)}{(Number of Classes)} = \frac{(Range of Data)}{(Number of Classes)}$

Step 2

The number of classes can be estimated using the rounded output of Sturges' rule, $N = 1 + 3.322 \log (n)$ , where $N$ is the number of classes and $n$ is the number of items in the data set.

$1 + 3.322 \log (7) = 3.80741568$

Step 3

Select $4$ classes for this example.

$4$

Step 4

Find the data range by subtracting the minimum data value from the maximum data value. In this case, the data range is $9 - 0 = 9$ .

$9$

Step 5

Find the class width by dividing the data range by the desired number of groups. In this case, $\frac{9}{4} = 2.25$ .

$2.25$

Step 6

Round $2.25$ up to the nearest whole number. This will be the size of each group.

$3$