Question

which of these is a true null hypothesis? does taking an aspirin daily help prevent heart attacks? taking aspirin daily does not affect heart attack risk.

Explanation:

A null hypothesis typically states that there is no effect or no relationship between variables. The first option is a question, not a hypothesis. The second option ("Taking aspirin daily does not affect heart attack risk") states no effect between aspirin intake and heart attack risk, fitting the null hypothesis definition.

Answer:

Taking aspirin daily does not affect heart attack risk.