Are you sure you want to leave?

Your test is still in progress. If you leave this page or go back now, all your attempt wil not be saved.

Helena, an amateur marine biologist, is studying the population of sea turtles. She studied the area of Jervis beach for 5 years and recorded every sighting of turtles.

Helena: “The turtle population is in danger! Their numbers have dropped by 20% between 2014 and 2015."

Which of the following statements shows the mistake Helena has made?