RECAP

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URBP 204 A Class 3
RECAP What is not Research What is Research
Research approaches (idiographic, nomothetic,
inductive, deductive) Social Science Paradigms
(viewpoints, lens) Elements of Social
Theory (observation, facts, laws, theory,
conceptions, concepts, variables, postulates,
propositions, hypotheses) Measurement Conceptual
ize (QOL) Operationalize (side walks, crime)
Measure (nominal, ordinal, interval, ratio)
Quality of measurement (precision, accuracy,
reliability, validity) Research ethics
(voluntary participation, no harm,
anonymity/confidentiality, deception, truthful
analysis/ reporting, politics and ideology)
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URBP 204 A Class 3

• Topics in this class
• Measurement (from Class 2)
• Research Ethics (from Class 2)
• Give out Exercise Set 1
• Descriptive Statistics
• Excel and SPSS Tutorial

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URBP 204 A Class 3

• Descriptive Statistics
• Used to describe the data. Mean, Median, Mode,
  Standard
• Deviation, Variance, Range, Quartiles.
• Inferential Statistics
• Used to infer from the data (sample) about the
• whole population. Statistical Significance
• T-Test of Dependent Samples (also called T-Test
  of Related Groups)
• T-Test of Independent Samples (also called
  T-Test of Unrelated
• Groups)
• Analysis of Variance (ANOVA)
• Factorial Analysis of Variance
• One Way or One Factor Chi- square and
• Two Way or Two Factor Chi Square

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URBP 204 A Class 3
Understanding Averages Measures of central
tendency Mean, median, and mode Importance of
being mean How much on an average will a house
sell for in this neighborhood? Ms. Johnsons
House 600,000 Mr. Woods House 400,000 Ms.
Browns House 500,000 Total observations
3 Mean (600,000 400,000 500,000)/ 3
1,500,000/3
500,000 Mathematically X ?X N On an
average a house will sell for 500,000
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URBP 204 A Class 3
Downside of being mean Sensitive to extreme
values. Ms. Johnson House 600,000 Mr. Woods
House 400,000 Ms. Browns House 500,000 Total
observations 3 Mean (600,000 400,000
500,000)/ 3 1,500,000/3
500,000 If instead of 600,000, Mr. Johnsons
house sells for 2.4 million Then mean
(2,400,000 400,000 500,000)/3
3,300,000/3 1,100,000 1.1
million! HENCE WE NEED THE MEDIAN!
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URBP 204 A Class 3
Median Mid-point of a set of values Ms.
Johnsons House 600,000 Mr. Woods
House 400,000 Ms. Browns House 500,000 Value
s in increasing order 400,000, 500,000,
600,000 Median 500,000 Ms. Johnsons
House 2,400,000 Mr. Woods House 400,000 Ms.
Browns House 500,000 Values in increasing
order 400,000, 500,000, 2,400,000 Median
500,000
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URBP 204 A Class 3
Median Contd.. If there are even number of
values in the data set then take average of the
two middle values Ms. Johnsons
House 600,000 Mr. Woods House 400,000 Ms.
Browns House 500,000 Mr. Whites
House 450,000 Values in increasing order
400,000, 450,000, 500,000, 600,000 Median
(450,000 500,000)/2 475,000
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URBP 204 A Class 3
Mode My computer (or is it me!) is in sleeping
mode! Mode is the value that occurs most
frequently Example of house price Value
Frequency 200,000 1 244,000 5 567,000 3 12
3,000 4 Mode is 244,000 E.g. votes for
candidate Value Frequency Candidate
X 234,000 Candidate Y 123,000 Candidate
Z 199,000 Mode is Candidate X
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URBP 204 A Class 3
Variability Why cant we all be the
same!!!! 20,20,20,20,20,20 Mean
20 20,21,19,20,18,22 Mean 20 6,26,33,7,40,0 Me
an 20 Which set of data has most
variability? Variability, a.k.a. spread or
dispersion, measures how different the values are
from each other by measuring how different the
values are from the mean. 3 measures of
variability Range, Standard Deviation, and
Variance
Note the class notes summarize the Babbie (2004)
Chapters 4, and 6.
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URBP 204 A Class 3
Range 20,20,20,20,20,20 Mean 20 Range
20-20 0 20,21,19,20,18,22 Mean 20 Range
22-18 4 6,26,33,7,40,0 Mean 20 Range 40-0
40 Range highest score lowest
score Standard Deviation Average distance from
the mean Example Home runs scored by Yankees in
last 9 games 2,2,3,4,5,5,8,9,10 Mean total
home runs/number of games 48/9 5.33 Standard
deviation s ?(X- X)2 n-1
Note the class notes summarize the Babbie (2004)
Chapters 4, and 6.
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URBP 204 A Class 3
Standard Deviation contd Standard deviation
s ?(X- X)2
n-1 Game No. Scores (X) Mean (X)
(X-X) (X-X)2 1 2 5.33 2-5.33
-3.33 11.0889 2 2 5.33 2-5.33 -3.33
11.0889 3 3 5.33 3-5.33 -2.33
5.4289 4 4 5.33 4-5.33 -1.33
1.7689 5 5 5.33 5-5.33 -0.33
0.1089 6 5 5.33 5-5.33 -0.33
0.1089 7 8 5.33 8-5.33 2.67
7.1111 8 9 5.33 9-5.33 3.67
13.4689 9 10 5.33 10-5.33 4.67
21.8089 n9 ?(X- X)2
72.001 Std. deviation s ?(X- X)2
72.001 72.001 9.000 3
n-1 9-1 8

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URBP 204 A Class 3
Standard Deviation contd When is the standard
deviation 0? WHEN THERE IS NO VARIABILITY! Game
No. Scores (X) Mean (X)
(X-X) (X-X)2 1 2 2 2-2 0 0 2 2 2
2-2 0 0 3 2 2 2-2 0 0 4 2 2
2-2 0 0 5 2 2 2-2 0 0 6 2 2
2-2 0 0 7 2 2 2-2 0 0 8 2 2
2-2 0 0 9 2 2 2-2 0 0 n9
?(X- X)2 0 Std. deviation s ?(X-
X)2 0 0 0 0
n-1 9-1
8
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URBP 204 A Class 3
Variance Just square the standard deviation! If
standard deviation 3 Then variance 32 9