These notes are not intended as a substitute for attending class. They include links to WEB sites discussed in class and an outline of class discussions and in-class activities. If you miss class, check the class notes for information on class discussions and on in-class assignments that should be submitted to WEBCT by those who miss class. These notes will be used on the screen in class, and will be edited during the class. Be sure to reload this file each time you check it, to make sure you have the latest version.
January 23:The goals and organization of the course. Discussion of WEBCT and how to do online assignments. Installation of the Microcase Software from the CD-ROM and disk included at the back of the workbook packaged with your text.
Jan 25: Use of the WEBCT system, including how to submit assignments. We will work on the first assignment, and go over to the computer center for individual help as needed - computer lab 108/109. Use of the Microcase Software for the Introductory Assignment.
January 28: Today we will discuss the nature and uses of science and social science. How does social science differ from other ways of thinking: poetry, philosophy, theology, physical science? We will discuss several documents: Three approaches to knowledge. W.H. Auden's poetry. For a sample of a new concept, click on virtropy. Is this a good concept? Why or why not? Census Document on Racial and Ethnic Categories. Brazilian Racial Categories. Other concepts we can consider are: poverty, power, crime, murder, race, IQ, liberalism/conservatism, homelessness. Or we could look at Personality Types as defined by Carl Jung and Measured by Isabel Meyers-Briggs. There are also techniques such as concept mapping that can be used to develop concepts. Example: data on the Bureau of Justice Statistics WEB site.
January 30: Use of Microcase, overview of the Introductory Exercise.
February 1: Discussion of designing research projects. How do we decide what to study? Supplementary reading in Trochim on the structure of research. You may prefer his "hourglass" metaphor to the circular one on page 14 of our textbook.
Feb 4 - Percentages and Expected Frequencies
Overview of Assignment 2b, primarily the use of crosstabs to compute percentages.
Looking at the frequencies for GOVMED we see that there are 1849 respondents and 896 thought the government should help. To make that a percent we divide the 896 by 1849, getting .4845. Move the decimal two columns to the right and we get 48.5%. Percents always add to 100%, you don't know what they mean if you don't know how they add to 100%. The base of the percent is the 100%, in this case 1849 people are 100% of the respondents. The phrase "of the" tells you the base of the percent.
When I ask you what percent is something, you should say: Percent of what?
Taking the number of people who
are liberal and favor Government Help, we could ask three questions:
1. Column percent:
What percent
of the liberals
think that the government should help?
2. Row percent:
What percent of those who think the government
should help are liberals?
3. Total Percent:
What percent of the respondents
are liberals who think the government should help?
Row, column and total percentages. A percentage is a ratio between a frequency and a base. In a sentence, the base follows the word "of." For example, if I say, what percent of the voters voted for Bush, the base is the number of voters. This is the denominator in the calculation. The numerator is the number voting for Bush.
For example, assume that:
75 men voted for Bush
95 women voted for Bush
35 men voted for Gore
125 women voted for Gore.
We could put this into a Table:
| Men | Women | Total | |
| Bush | 75
56.65 |
95
113.3 |
170
.515 |
| Gore | 35
53.28 |
125
106.7 |
160
.484848 |
| Total | 110 | 220 | 330 |
The espected frequencies are
a form of "null hypothesis." The null hypothesis is that there is
no relationship between gender and voting. If this were the case,
what percent of the men would we expect to vote for Bush? The answer
to that is, the same percent as voted for Bush in the total sample.
The same for the women. What percent of the sample voted for Bush
170/330 which is ????%. As a proportion it is .???. Using
this proportion, we cancompute the "expected frequencies," these are the
frequencies we would "expect" under the null hypothesis that there is no
difference between the genders. To compute those, we take the PROPORTION
voting for Bush and multiply it by the number of men and then the number
of women. .515 * 110 = 56.65 men. This
is not a percent, it is a frequency. .515
* 220 = 113.3 women.
.485
* 110 = 53.24
.485 * 220 =
Another way to compute expected frequencies is rt * ct/gt where rt = row total, ct = column total and gt = grand total. This is probably easier, but it doesn't help you to understand what the number "means".
On the first test, you will be asked to answer specific questions such as:
How many men were there in the sample? 110
How many women were there in the sample? 220
How many respondents are there? 330
How many respondents voted for Bush? 170
How many respondents voted for Gore? 160
On the null hypothesis that there is no relatinship
between gender and vote, how many women would we expect to vote for Bush?
What percentage of the men voted for Bush? (column percent) 75/110 = .682 or 68.2%.
What percentage of the Bush voters were men? (row percent)n 75/170 = 44.1%
What percentage of the voters
were men who voted for Bush? (total percent)
75/330 = 22.7%
What percentage of the women voted for Bush? (column percent) 95/220 = 43.2%-
The Chi Square Statistic tells us whether the difference
between the "expected" frequencies and the "observed" frequencies is statistically
significant. The first few pages of this
Chi
Square lesson by Amar Patel explain the meaning of "expected" frequencies.
It also goes on to explain the computation of chisquare. An Example:
Alleged Racial Profiling by the San Diego Police. Here
is a one page summary
of what we need to know about chisquare. Have some data
you want to test with chi square? Use the WEB
Chi Square Calculator.
Feb 6 Levels of Measurement.
Variables vs. Constants - variables are characteristics or aspects that take different values among the things being studied (the units of analysis). The task of social science is to explain variation, metaphysics deals with constants.
This follows from conceptualization - that is how we think of the "thing" being measured. For example, race. What is it? Glenn C. Loury defines it as: "a cluster of inheritable bodily markings carried by a largely endogamous group of indiduals, markings that can be observed by others with ease, that can be changed or misrepresented only with great difficulty, and that have come to be invested in a particular society at a given historical moment with social meaning." The Anatomy of Racial Inequality, p. 20.
Suppose we were to measure race, how would we do it?
Our goal is to conduct a census of the US population and determine how
many people there are of each race. We ask people to check
a box indicating their race. What are the boxes? Today the
official
categories are:
In Brazil, the categories are different, as Jennifer Roth
Gordon reports: black, white, brown, yellow, also native Brazilian.
The people look the same. Conceptions of race in Brazil challenge
Americans to go beyond fixed, blood or biologically based categories and
see race as fluid, often individually defined, and even seasonal. When
race is defined as skin color (which is much of the time in Brazil), being
tan from the sun can affect the way you identify. Though the Brazilian
census asks individuals to identify as black (negro), white (branco), brown
(pardo), or yellow (amarelo), many Brazilians commonly refer to themselves
as moreno (or brown). While
blackness
is both socially and economically stigmatized, extreme whiteness is also
considered marked (though not economically disadvantageous). Caught between
American Brazilianists who argue for all mixed Brazilians to discover their
blackness and other Brazilianists who would rather not see race in Brazil
in black and white, Brazilians negotiate fluid racial categories which
do not preclude a Brazilian kind of racism.
Hishram
Aidi reports that: A DNA study by Brazilian scientists
found that 80 percent of the population has at least some African ancestry,
and fully half of the nation's 165 million inhabitants consider themselves
to be of African descent. ...Myriad racial categories also hamper Afro-Brazilians'
ability to mobilize. A 1974 census presented 134 categories, ranging from
"bem-branca" (real white) to "bailano" (ebony). In the most recent census
only 6 percent of Brazilians classified themselves as black, while 40 percent
preferred the term "pardo" ("brown") — and others chose one of the 100
different terms to describe their skin tone: "criolo," "moreno," "mulato",
"mestico."
So it is difficult to know, in many cases, exactly what
we are talking about. This is true of other sociological terms such
as "social class" Are there distinct social classes? In 16th
century France, Society is still very much divided into the three
traditional estates: those who pray (the church), those who fight (the
nobility), and those who work (everyone else). In The Communist Manifesto:
The history of all hitherto existing society [2] is the history of class
struggles. Freeman and slave, patrician and plebian, lord and serf, guild-master
and journeyman, in a word, oppressor and oppressed, stood in constant opposition
to one another, carried on an uninterrupted, now hidden, now open fight,
a fight that each time ended, either in a revolutionary reconstitution
of society at large, or in the common ruin of the contending classes.
But what about in American society today? What
classes are there? Upper, Middle, Lower? Upper, Middle, Working,
Lower? UU LU UM LM UL LL? How would we sort people into these
categories? In his book Yankee City, Lloyd Warner and his associates
broke each of the three classes into an
upper and a lower section.
The top, or upper-upper class, is composed of the wealthy old
families, who have long been socially
prominent, and who have had money long enough for
people to have forgotten when and
how the fortune was acquired. For example, how many
of you know how Joseph Kennedy,
the father of President John Kennedy, made his
fortune? The lower-uppers
may have as much money, but have not had it as long, and their
family has not been socially prominent
as long. The upper-middle class includes most of
the successful business and professional
persons, generally of "good" family background
and comfortable income. The
lower-middle class includes clerks, other white-collar
workers and semiprofessionals,
and possibly some foremen and top craftsmen. The
upper-lower class consists mainly
of the steadily employed workers, and is often described
as the "working class" by those
who feel uncomfortable about applying the term "lower"
to working individuals. The
lower-lower class includes the irregularly unemployed, the
unemployable, migrant laborers,
and those living more or less permanently on public
assistance.
Or do we have continuous stratification, should we talk
about "socio-economic status" (SES) instead? In that case we would
average together indicators such as Income, Years of Education and Occupational
Status. We would have a continuous numerical distribution, not sharp
categories.
This gets us into the topic of levels of measurement,
no matter what we are measuring, we have to choose a level of measurement:
I will discuss six categories (two of which are not in the book):
Units of Analysis - you cannot necessarily generalize findings about one unit, such as a state or other ecological entity, and another, such as the people who live in it. If you find that states with more money have a higher rate of alcohol consumption, you cannot say that it is the wealthier people in the state who drink. This error is called the "ecological fallacy."
Our main topic today is the Quality of Measures. How do we evaluate and measure the quality?
Reliability means Consistency. Between raters, between testings, between forms of a test, between halves of a test, or between the items of a test. With questionnaires, we measure inter-item and item-total correlations. Cronbach's alpha is a widely used statistical measure of inter-item reliability.
Validity is a much more difficult concept. It asks whether the variable measures the concept it is supposed to measure. This is a philosophical question, what does something really "mean". This is problematic with concepts such as "intelligence" that are unclear in themselves. There are several criteria.
February 11 - Today we will look at the varieties
of measures used in sociology and criminal justice, with a focus on Questionnaire
Construction.
February 13 -
Use of the "collapse" option in Microcase, pages 51-52 in the Workbook. The purpose here is to eliminate columns cases where we have insufficient data. We can also combine columns which allows us to reconceptualize our data, e.g., combine all minorities into a single "nonwhite" category.
Demonstration of Exercise 3 in the Workbook, pages 69 to 79. They key point here is to look at the details of how the variables are measured. It is particularly important to look at whether a variable is a raw frequency, e.g., the number of Playboy subscribers, or a rate, e.g., the number of Playboy subscribers per 100,000 population. We can use Microcase to convert data to rates if they don't come that way in the data set.
We can assess the reliability of a measure that consists of several items by looking at the item-total correlations, or the inter-item correlations, or the Cronbach's alpha, which is a similar measure. We can assess construct validity by doing cross-tabulations or correlations, depending on the way the variables are measured, and seeing if the relationships work out as our theory says they should. Looking at relationships between variables is more meaningful than looking at the distributions on a single variable when the variable uses terms that are not precisely specified, e.g., if people say they "strongly favor" something, we don't know have a good idea of what that means until we compare it to how many favor other things.
February 15 - Review for First Exam. We will look at some sample multiple choice questions and do some math questions on paper. Bring a calculator.
Feb 18 - first exam - Feb 20 discussion
of exam items.