Question

A placement test is administered to collegiate freshmen. The test is known to be approximately normal with a mean of 65 and a standard deviation of 5. Sheila scored a 59 on this test. Does this score place Sheila in the bottom 10% of test takers?

Answer 1

Answer: D. She is above 11.5% of test takers

Step-by-step explanation:

So logically we can eliminate like 3 answers and let me explain why

So first we can eliminate both A and B because the question asks "Does this score place Sheila in the bottom 10% of test takers?" If the answer were yes she wouldn't be "above 8.5%" or "above 11.5%" because she would be below.

So that would leave both C and D right. Lets look at C first. It says "No, she is above 8.5% of test takers" But if she is above 8.5% she could hypothetically be in the 9% or the 9.5% of test takers. Since this answer doesn't gurantee she would be above 10% we can't choose it. Now D it says "No, she is above 11.5% of test takers" This is correct because She is not in the bottom 10% because according to the empirical rule she is I would say around or just under 16% of test takers. Also the 11.5% part gurantees that anything above the number 11.5 is greater than 10%. Unlike in C which only says the number is greater than 8.5 which means the number could be 8.6 which is NOT greater than 10.