Chapter 2, Problem 1CQQ

To determine

To calculate the class width of the frequency distribution.

Answer to Problem 1CQQ

The intervals have equal class widths of $0.04$ g/dL.

Explanation of Solution

The first two classes of frequency distribution are $0.08-0.11\text{ and }0.12-0.15$ .

The two classes are inclusive class intervals as they include the upper and lower limit values.

To find the class width, first convert the intervals from inclusive to exclusive type.

Add half of $0.01$ to upper limit and subtract from lower limits of the two intervals, to make them exclusive.

  $\begin{array}{l}0.08-\left(1/2\times 0.01\right) =0.075\hfill \\ 0.11+\left(1/2\times 0.01\right)=0.115\hfill \\ 0.12-\left(1/2\times 0.01\right) =0.115\hfill \\ 0.11+\left(1/2\times 0.01\right)=0.155\hfill \end{array}$

The exclusive intervals are $0.075-0.115\text{ and }0.115-\mathrm{0.155.}$

Hence, the class width for the first interval is

  $\begin{array}{l}0.115-0.075\\ =0.04\end{array}$

For the second- class interval, it is:

  $\begin{array}{l}0.155-0.115\\ =0.04\end{array}$

The intervals have equal class widths of $0.04$ g/dL.