In the experiment, students put brine shrimp in water with different concentrati
ID: 87864 • Letter: I
Question
In the experiment, students put brine shrimp in water with different concentration of salt and counted the number.
Which of the following changes to the experiment will increase confidence in the validity of the result?
Count the number of dead brine shrimp instead of living brine shrimp
Add more brine shrimp to the water with the highest salt concentration
Repeat the experiment several times, and calculate the average number of brine shrimp
Reduce the length of the experiment from 24 hours to 8 hours.
Explanation / Answer
The correct answer is : Repeat the experiment several times, and calculate the average number of brine shrimp.
Reason :
Let us first focus on the topic of the experiment, the student puts brine shrimp in water of different salt concentration probably to determine the survivability of the brine shrimp at different salt concentration.
So he counts the number of alive shrimps at a particular concentration at the end of the experiment to draw an inference.
So to get a more reliable inference he should repeat the experiment several times, count the no of surviving shrimp in each concentration and calculate an average of the surviving shrimp in each dilution. This would validate the result and increase confidence inthe findings.