Interactive practice questions
A scientist investigated the link between the number of cancer cells killed by a certain drug and the strength of the drug used. The results were recorded and the coefficient of determination $r^2$r2 was found to be $0.92$0.92.
Which of the following is true?
Select all that apply.
There is a strong relationship between the strength of the drug used and the cancer cells killed.
The number of cancer cells killed causes the strength of the drug used.
We cannot infer a causal relationship between strength of the drug used and the cancer cells killed.
The strength of the drug used causes the cancer cells to be killed.
There is a weak relationship between the strength of the drug used and the cancer cells killed.
Dave sells bicycles. He thinks that he sells more bicycles when there is a full moon. He recorded his number of sales during the different moon phases.
The results were recorded and the resultant coefficient of determination $r^2$r2 was found to be $0.19$0.19.
Mae has a small herb garden with a thyme plant. She suspects that the growth of the thyme plant is exponentially dependent on the amount of tea she drinks.
For a month she keeps a daily log of the amount of tea she drinks and the millimetres that the thyme plant has grown .
The resultant coefficient of determination $r^2$r2 was found to be $0.13$0.13.
Shannon is convinced that the number of watch factories in a town is directly related to the number of department stores in that town. Shannon collects data on the number of watch factories and department stores in different towns across the country.
The resultant coefficient of determination $r^2$r2 was found to be $0.44$0.44.