STAT 100 Chapter 9: Chapter 9 STATS.docx

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azuregoldfish420

30 Mar 2012

School

Simon Fraser University

Department

Statistics

Course

STAT 100

Professor

Derek Bingham

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Document Summary

Common way to mislead with data is to cite correct numbers that don"t quite mean what they appear to say because we aren"t told the full story. The numbers are not made up, so the fact that the information is a bit incomplete may be an innocent oversight. If you don"t know the context, the lonely, isolated, naked number doesn"t tell you much. Too much precision or regularity can lead to the same suspicion. The laboratory instructor knows that the accuracy of the equipment and the student"s laboratory technique are not good enough to give such perfect results (the student made them up) Suspicious regularity (identical data points) combined with inconsistency (different numbers of animals) led a careful reader to suspect fraud. Percentage change = amount of change/ starting value x 100. Pay attention to voluntary response samples and to confounding. See if there are any missing information.

Related Questions

Carol holds a two-digit number X and wants Alice and Bob to recover the number. She gives them the following information.

Both Alice and Bob know that the number held by Carol is one of the following.

21 26
31 32 35
42 44
52 54 57
62 67

Alice knows the number of ones of X but not the number of tens.
Bob knows the number of tens of X but not the number of ones.

Alice and Bob exchange the following messages.

(a) Bob to Alice: ’You might know X’.
(b) Alice to Bob: ’I did not, but, after what you have said, I do’.

Based on the above information, please answer the following questions. For each question, please accompany your answer with a short explanation of why your believe your answer is correct. Marks will not be awarded for answers without any explanation.

(a) Based on the statement of Bob it is possible to narrow down candidates for the number of tens from the initial five possibilities down to just two. What are these two possibilities? (7 marks)
(b) Based on the ’I did not’ statement of Alice, the number of candidates for X can be narrowed down to just three. What are these candidates (6 marks)
(c) The remaining part of Alice’s statement allows to identify X precisely. What is X? (7 marks)

cerisewombat429

Which sample fairly represents the population? Check all that apply.

1) measuring the heights of every fiftieth person on the school roster to determine the average heights of the boys in the school.

2) calling every third person on the soccer team’s roster to determine how many of the team members have completed their fundraising assignment observing every person.

3) walking down Main Street at 5 p.m. one evening to determine the percentage of people who wear glasses.

4) sending a confidential e-mail survey to every one-hundredth parent in the school district to determine the overall satisfaction of the residents of the town.

5) taking a poll in the lunchroom (where all students currently have to eat lunch) to determine the number of students who want to be able to leave campus during lunch