Question

a researcher finds that students who sleep more tend to get higher grades. which of the following conclusions is valid? more sleep definitely causes higher grades. there is no relationship between sleep and grades. higher grades cause students to sleep more. there is a correlation, but we cannot say that more sleep causes higher grades without further evidence.

Explanation:

The research only observes a trend that more sleep is associated with higher grades, but correlation does not equal causation. There could be other confounding variables (like study habits, overall health) that explain both more sleep and higher grades. We cannot confirm a causal relationship without further controlled evidence. The first option incorrectly assumes definite causation, the second contradicts the observed trend, and the third reverses a causal claim without evidence.

Answer:

There is a correlation, but we cannot say that more sleep causes higher grades without further evidence.