Line Plots and Fraction Data

A line plot scale can be marked in halves, quarters, or eighths.

Adding the measurements

Three beakers at 3/8 litre hold 9/8 litres between them.

Sharing it out again

Pouring all the liquid together and sharing it equally is a total, then a division.

Fractional measurements on a plot

Measuring to the nearest eighth of an inch produces values like 2 3/8 and 3 1/8. The line plot's scale must show every eighth, evenly spaced, so each measurement has a place to sit whether or not anything landed there.

Adding all the measurements

Finding the total length of everything measured means adding a list of fractions — real work for this chapter's skills. Convert everything to the same denominator first, add the numerators, then convert back to a mixed number.

Sharing the total out evenly

A common question asks what each item would measure if the total were shared equally. That is the total divided by the number of items — a fraction divided by a whole number, which is exactly what Chapter 7 covers.

What the shape tells you

A tall stack marks the most common measurement. A wide spread means high variation. A mark far from the others deserves a second look — it may be a genuine outlier or a mismeasurement. Reading the shape is the point of plotting at all.