Math 151 , Fall 2006 Friday Day 21, Oct. 13 Hit reload...

HW:  (Re)Read Chapter 8.  Read p. 200 (Other designs) last (optional).  Check p. 206, 8.17-22, 26 at first., then 8.23-25 with Table B.  Next, Chapter 9.
Hand in  Monday

  p. 199 8.9 Apartment living, SRS. Use Table B.
p. 209, 8.36 Area code sample, SRS  Use Table B.
p. 211, 8.45 random digit dialing
p. 210, 8.41 random digit characteristics

p.209-10, 8.38 b only Traffic lights
p. 208, 8.30 movie viewing

Read, to discuss 


p. 211, 8.47 guns

p. 204, 8.14, 8.15 biases.
p. 208, 8.31 world affairs
p. 211, 8.46 wording survey questions


Optional 
p. 209, 8.35 Use table B (more practice)

p. 209, 8.34 seat belt use

Exams returned.  More discussion Monday.  Solutions outside my door/on reserve.
Problem#
  total
 1 2 3 4 5 6 7 0    
9|555
possible 102 5 18 12 14 21 6 21 5      
9|00111
max 95 5 18 12 14 21 6 21 5
8|69
Q3 91 5 18 10 12 20 6 18 5
8|334
Med 84 3 18 10 11 18 6 15 5
7|77
Q1 74 3 15 9 11 15 3 12 5
7|4
min 53 1 10 6 9 2 0 2 5
6|5











6|03











59, 53
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Homework questions:  Day 20

recap: Sampling
>>Population: Entire group  that we want information about.
>>Sample: The part of the population we actually examine.
      Hope:  Sample will be representative of the population.
>> Sampling design:  Describes exactly how sample is to be chosen from population.

(SAMPLING) BIAS:  The design of a study is biased if it systematically favors certain outcomes.  
Non-probability samples (sampling badly): Voluntary response sample , Convenience sample

Our main sampling design:
Simple Random Sample (SRS) of size n:  n individuals chosen in such a way that every possible set of n individuals has an equal chance of being chosen.  See Day 20 for details.

Some more sources of bias  See Day 20 for details.
**Undercoverage:     One possible source of undercoverage: Sampling frame excludes some.
** Nonresponse
**Response bias
**Wording of questions

 A probability sample (p.200) is from a design where impersonal chance is used to pick the individuals.  SRS is the most straightforward.  More sophisticated methods are often used  but they're optional this term. (More info)

Sievers home   Math151-Fall06/Daym21.htm  11pm 10/12/06
This page belongs to Sally Sievers who is solely responsible for its content. Please see our statement of responsibility.