Question 15 Marks
Draw frequency polygons for each of the following frequency distribution:$(a)$ using histogram$(b)$ without using histogram
| $C.I$ | $5 -15$ | $15 -25$ | $25 -35$ | $35 - 45$ | $45-55$ | $55-65$ |
| $ƒ$ | $8$ | $16$ | $18$ | $14$ | $8$ | $2$ |
Answer
View full question & answer→Using Histogram:
Steps:

Without using Histogram:
$1$. Find the class$-$mark $($mid$-$value$)$ of each given class$-$interval.
$2.$. On a graph paper, mark class$-$marks along $X$-axis and frequencies along $Y-$axis.
$3.$ On this graph paper, mark points taking values of class$-$marks along the $X-$axis an values of their corresponding frequencies along the $Y-$axis.
$4.$ Draw line segments joining the consecutive points marked in step $(3)$ above.

| $C.I.$ | $f$ |
| $5 - 15$ | $8$ |
| $15 - 25$ | $16$ |
| $25 - 35$ | $18$ |
| $35 - 45$ | $14$ |
| $45 - 55$ | $8$ |
| $55 - 65$ | $2$ |
- Draw a histogram for the given data.
- Mark the mid$-$point at the top of each rectangle of the histogram drawn.
- Also, mark the mid$-$point of the immediately lower class$-$interval and mid$-$point of the immediately higher class$-$interval.
- Join the consecutive mid$-$points marked by straight lines to obtain the required frequency polygon.

Without using Histogram:
$1$. Find the class$-$mark $($mid$-$value$)$ of each given class$-$interval.
$2.$. On a graph paper, mark class$-$marks along $X$-axis and frequencies along $Y-$axis.
$3.$ On this graph paper, mark points taking values of class$-$marks along the $X-$axis an values of their corresponding frequencies along the $Y-$axis.
$4.$ Draw line segments joining the consecutive points marked in step $(3)$ above.
| $C.I.$ | Class$-$mark | $f$ |
| $-5 - 5$ | $0$ | $0$ |
| $5 - 15$ | $10$ | $8$ |
| $15 - 25$ | $20$ | $16$ |
| $25 - 35$ | $30$ | $18$ |
| $35 - 45$ | $40$ | $14$ |
| $45 - 55$ | $50$ | $8$ |
| $55 - 65$ | $60$ | $2$ |
| $65 - 75$ | $70$ | $0$ |













