In order to draw a frequency polygon by using a histogram, which of the following statements is incorrect?
Obtain the mid-points of three class- intervals of highest frequency on Y-axis, one adjacent to the first on its right and one adjacent to the last, on its left
To draw a frequency polygon, you have to obtain the mid-points (class marks) of TWO imagined class-intervals of ZERO frequency, which is on X-axis, one adjacent to the first, on its LEFT and one adjacent to the last, on its RIGHT. Then complete the polygon by joining the mid-points (class marks) of first and last imagined class-intervals to the mid-points of the adjacent rectangles.