Scottish researchers compared rates of depression between 94 undergraduates who regularly kept diaries and 41 students who did not. They found that people who kept diaries were more likely to have depression than those who did not. The researchers said, "We expected diary-keepers to have some benefit, or be the same, but they were the worst off. You are probably much better off if you don't write anything at all." Their interpretation of the results was flawed because the researchers assumed an order of cause and effect. Their interpretation of the results was correct because writing in a diary probably causes one to think too much on their problems, leading to depression because they dwell on their problems too much. O Another explanation could be that people who are depressed are more likely to keep a diary. O This is an observational study, so it is not possible to ascribe that writing in a diary (cause) leads to depression (effect).

A student needs to answer 20 out of 30 questions on a test. Find the number of ways the student can choose if the student must answer the first 8 questions on the test.

Please help me answer the following questions. Thank you

could you specify the answer?