91影视

Data are given on the ages of the best actresses when they won the Oscar.

The class width of an interval is computed by subtracting a lower class limit from the succeeding lower class limit.

Here, the lower class limit of the first class interval is equal to 20, and the lower class limit of the second class interval is equal to 30.

$$\begin{gathered} \text{Class}\text{width}=30-20 \\ =10 \end{gathered}$$

As it can be observed that all class intervals have equal width, the class width for each interval is equal to 1.

The midpoint of a class interval has the following expression:

$\text{Midpoint}=\frac{\text{Lower}\text{limit}+\text{Upper}\text{limit}}{2}$

Thus, the midpoints of the class intervals are computed as shown below.

To compute the class boundaries, the value of the gap between each successive interval divided by 2 is subtracted from the lower limit and added to the upper limit of a class interval.

The gap is calculated as shown below.

$$\begin{gathered} \text{Gap}=2^{nd}\text{lower}\text{class}\text{limit}-1^{st}\text{upper}\text{class}\text{limit} \\ =30-29 \\ =1 \end{gathered}$$

The value equal to$\frac{1}{2}=0.5$is subtracted from the lower class limits and added to the upper-class limits of each interval. Thus, the class boundaries are obtained as shown below.

Therefore, the class boundaries are 19.5, 29.5, 39.5, 49.5, 59.5, 69.5, 79.5, and 89.5.

The sum of all the frequencies gives the total number of individuals included in the given frequency distribution.

$$\begin{gathered} \text{Total}\text{frequency}=29+34+14+3+5+1+1 \\ =87 \end{gathered}$$

Therefore, the total number of individuals included in the given frequency distribution is equal to 87.