Final answer:
James Lind conducted an experiment on scurvy. He divided the sailors into pairs and gave each pair a different daily supplement. The experiment showed that sailors who drank cider had some improvement in their scurvy symptoms.
Step-by-step explanation:
James Lind conducted an experiment on scurvy. He chose a group of 12 sailors with scurvy and divided them into 6 pairs. Each pair received a different daily supplement while all sailors had the same diet. The experiment showed that the sailors who received a quart of cider had some improvement in their scurvy symptoms, supporting the idea that citrus fruits can cure scurvy.
In Lind's experiment, the independent variable was the daily supplement received by the pairs, and the dependent variable was the improvement/no improvement in scurvy symptoms.
Lind's small sample size of 12 sailors is considered small by modern scientific standards, but it still provided valuable insights into the effects of citrus fruits on scurvy.