Blood clotting is due to a sequence of chemical reactions. The protein thrombin initiates blood clotting by working with another protein, prothrombin. It is common to measure an individual's blood clotting time as prothrombin time, the time between the start of the thrombin- prothrombin reaction and the formation of the clot. Researchers wanted to study the effect of aspirin on prothrombin time. They randomly selected 12 subjects and measured the prothrombin time (in seconds) without taking aspirin and 3 hours after taking two aspirin tablets. They obtained the following data. Does the evidence suggest that aspirin affects the median time it takes for a clot to form? Use the α = 0.05 level of significance.

Transcribed Image Text:

Before After Before After Aspirin Subject Aspirin Aspirin Subject Aspirin 12.3 12.0 11.3 10.3 12.0 12.3 8. 11.8 11.3 3 12.0 12.5 9 11.5 11.5 4 13.0 12.0 10 11.0 11.5 13.0 13.0 11 11.0 11.0 12.5 12.5 12 11.3 11.5