# SOAN 2120 Study Guide - Final Guide: Central Tendency, Confidence Interval, Experiment

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SOAN 2120 EXAM REVIEW

Chapter 4 - Quantitative methods (4 questions on final exam)

Mean

average

measure of central tendency

add up all the scores, then divide by the number of scores

Median

Middle number

measure of central tendency

the middle point the 50th percentile - or the point where half the cases are above it, and half the

cases are below it

Mode

Most occurring number

measure of central tendency

can have more than one mode

Bimodal

A distribution with two modes

with two numbers that occur the most frequent

Multimodal

a distribution with more than one mode

can have 5 modes lets say

Normal distribution

A bell shaped frequency distribution

peak in the center, identical curving slopes on either side

3 measures of central tendency are equal

Skewed distribution

a frequency distribution that is not normal (not bell shaped)

More cases are at one end of the extremes

- If the distribution is skewed more to the left = positive; mean > median

- If the distribution is skewed more to the right = negative; mean < median

Code Book

A document that describes the procedure of coding variables and their location in a format for

computers

Pre-coding

- Placing the code categories on the questionnaire

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- (ex: 1 for man, 2 for woman, 3 for trans, 4 for other)

- If a researcher does not pre-code, the first step after collecting data is to create a

codebook

Bivariate

Bivariate statistics

statistical measures that involve only two variables

Correlation

Two variables are associated with one another

Independence

opposite of correlation

the absence of a relationship between 2 variables

Measures of Variation

Range

- a measure of dispersion for one variable indicating the highest and the lowest

scores

Percentile

- a measure of dispersion for one variable that indicates the percentage of cases

at or below a score or point

Standard deviation

- a measure of dispersion for one variable that indicates an average

distance between the scores and the mean

Z-scores

-the standard deviation and the mean are used to create z-scores

- used to express scores on a frequency distribution in terms of a number of standard deviations

from the mean

-(is it above or below the mean?)

Bivariate Table

- Presents the same information as a scatter plot, however in table format

Cross-tabulation

the cases are organized in the table on the basis of two variables at the same time

shows the percentage of cases at the intersection of categories of the two variables

Contingency table

a table showing the distribution of one variable in rows and another in columns

Used to study the association between the two variables

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There are 3 ways to percentage a table:

by row

by column

by the total

Marginals

The totals in a contingency table, outside the body of a table

Measure of association

A single number that expresses the strength, and often the direction of a relationship.

condenses information about bivariate relationship into a single number

Statistical significance

- Means the results are not likely due to chance factors

Level of statistical significance

- A way of measuring the degree to which a statistical relationship is likely due to chance

- 0.05 = you can be 95% confident that the results are due to a real relationship in the

population, not chance factors

Type 1 error

- Occurs when the researcher says a relationship exists, when in fact none exists

- Falsely rejecting the null hypothesis

Type 2 error

- Occurs when a researcher says a relationship does not exist, when in fact it does

- Falsely accepting the null hypothesis

Chapter 6- Field Research (7 Questions on final exam)

Ethnography and ethnomethodology

Ethnography

- an approach to field research that emphasizes providing a very detailed

description of a different culture from the viewpoint of an insider in that culture to permit a

greater understanding of it

- Ethno means people/folk and graphy refers to describing something

Ethnography is often considered a methodology rather than a method

Methodology

- a collection of data collection and analysis approaches that are linked

together through an overarching theoretical orientation

- Cultural knowledge includes explicit (what we know and talk about) and tacit knowledge

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