COVID-19 Positivity Rates in Ohio. An epidemiologist has collected data on positivity rates for COVID-19 testing in the state of Ohio. The positivity rate is defined as the number of tests that come back positive for the COVID-19 virus divided by the total number of COVID-19 tests completed. The epidemiologist has created the following chart showing positivity rates in Ohio between April and October 2020. The audience for this chart is interested in trying to gain insights into any overall increasing or decreasing trends in the positivity rate for COVID-19 during this time period.

a) How can this chart be improved to meet the needs of the audience?