Question

A student analyzes soil samples from her backyard. She organizes the samples into three categories, based on their pH. The three categories are: pH less than 8, pH between 8 and 8.5, pH greater than 8.5. Which type of graph should she use to show the percent of samples in each group?
stem and leaf plot

circle graph

line graph

scatter plot

Answer 1

Answer: circle graph.

Justification:

A circle graph (also known as pie chart) is excellent to visualize the relative size of different sectors. Being the entire circle 100%, each sector will show the percent of each category.

In the given example, the circle will be divided in 3 different sectors, in which the size is proportional to the percent of each one.

In the given case:: 

pH less than 8: 20%

pH between 8 and 8.5: 50%,

pH greater than 8.5: 30%


So, a sector whose area is 20% will represent the first category, a sector whose area is 50% will represent the second category, and a sector whose area is 30% will represent the third category. The whole circle is 100%, this is the sum of the 3 categories is 100%.