q6s - The SD is 0.5, either from the box 1 or from . 53 ....

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Math 127B, Quiz 6. Key. Thursday, March 17th, 2011 Name: Recitation Section: Ten minutes. Calculators allowed. 20 points maximum. 1. A coin is tossed 400 times. It lands heads 212 times. [ 20 points] (a) Based on this do you believe that there is evidence to support the claim that the coin is biased, i.e., not fair. Clearly state all the details of your test of significance. The expected percentage of heads is 50% under the null hypothesis. The alternative is that the coin is not fair. this may or may not be a box model. If the coins properties change with each toss, then they are not independent.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: The SD is 0.5, either from the box 1 or from . 53 . 47. The SE of the number is 400 . 5 = 10. The SE of the percentage is 10 / 400 100% = 2 . 5%. The score is z = (53-50) / 2 . 5 = 1 . 2. You can also do z = (212-200) / 10 = 1 . 2. The P-value is 12%. This is not signicant. We put the dierence down to chance variation. (b) How does your answer change if instead it had landed tails 212 times? It doesnt. Heads and tails are interchangeable in this problem under the assumption that the coin is fair! 1...
View Full Document

This document was uploaded on 10/29/2011 for the course MATH 127B at Vanderbilt.

Ask a homework question - tutors are online