Chapter 1.4, Problem 24E

Heal the Bay is an environmental organization that releases an annual beach report card based on water quality (Heal the Bay Beach Report Card, beachreportcard.org, retrieved May 7, 2016). The grades for 20 beaches in three counties in Washington (Whatcom, Snohomish, and Island counties) during dry weather were:

$\begin{array}{l}\text{C}\text{B}\text{A+}\text{A+}\text{A+}\text{A+}\text{A+}\text{A}\text{A+}\text{A+}\\ \text{A+}\text{C}\text{A+}\text{A+}\text{A+}\text{C}\text{A}\text{F}\text{F}\text{B}\end{array}$

Summarize the dry weather grades by constructing a relative frequency distribution and a bar chart.