Practice quiz: Reporting and reasoning

4 questions. Pick an answer to see if it is right. You can try as many times as you like. These are for practice: the final test has different questions.

1. 1.Which results sentence is most complete?

   The method was significantly better.Accuracy rose 2.1 points (95% CI 0.8 to 3.4; 5 seeds; paired t-test, p = 0.007).p < 0.05.Results were promising.
2. 2.r = 0.5. What share of the variation does the line explain?

   50%25%5%100%
3. 3.A test for a 1-in-1,000 disease is 99% sensitive with 1% false positives. After a positive result, the chance of disease is about...

   99%50%9%1%
4. 4.Why can r be near zero even when two variables are strongly related?

   r is always wrongThe relationship may be curved, like a U-shapeBecause of the p-valueIt can't