# Shared Flashcard Set

## Details

Social Statistics Exam #1
Key terms and concepts
44
Sociology
09/23/2012

Term
 Empirical Research
Definition
 Research that derives its data from direct observation or experiment To answer sociological research questions we cannot rely on reasoning, speculation, moral judgment, or subjective preference. EX: "What is the prevalence of binge drinking on college campuses?
Term
 Non-empirical question
Definition
 Requires judgment ex: "is binge drinking the most serious problem facing college campuses today?"
Term
 What is theory?
Definition
 theory- an explanation of the relationship between two or more observable attributes of individuals or groups
Term
 Role of theory
Definition
 used by social scientists to establish a link between what we observe(the data) and our understanding of why certain phenomena are related to each other in a particular way.
Term
 Hypotheses
Definition
 tentative answers to research questions (subject to empirical verification) that are derived from theories a statement of relationship betwen characteristics that vary (variables)
Term
 Population
Definition
 Population- the total set of individuals, objects, groups, or events in which the researcher is interested.
Term
 Sample
Definition
 Sample- a relatively small subset selected from a population We use samples to draw inferences about populations
Term
 Variables (definition)
Definition
 Variables- a property of people or objects that takes on two or more values that indicates a concept in the real world.
Term
 Dependent Variable
Definition
 Dependent variable- The variable to be explained (the "effect") The dependent variable is what you are trying to explain
Term
 Independent Variable
Definition
 Independent variable- the variable expected to account for (the "cause" of) the dependent variable. Usually occurs earlier in time than the dependent variable. The independent variable influences, directly or indirectly, the dependent variable. The value of the dependent variable depends on the value of the independent variable
Term
 Nominal level of measurement
Definition
 numbers or other symbols are assigned toa  set of categories for the purpose of naming, labeling, or classifiying the observations  Examples: Political party (democrat, republican) Religion (Catholic, Jewish, Muslim, Protestant) Race (African Americann, Latino, Native American)
Term
 Ordinal level of measurement
Definition
 Nominal variables that can be ranked from low to high (IN AN ORDER) Example: College Class Freshman Sophomore Junior Senior
Term
 Interval-ratio level of measurement
Definition
 Variables where measurements for all cases are expressed in the same units. Will also be a "pretty exact/specific" number. (Variables with a natural zero point, such as height and weight, are called ratio variables) Examples: Age Income SAT scores
Term
 Ratio Variables
Definition
 Ratio variables- Variables with a natural zero point, such as height and weight
Term
 Discrete variables
Definition
 variables that have a minimum-sized unit of measurement, which cannot be sub-divided EX: the number of children per family
Term
 Continuous variables
Definition
 variables that, in theory, can take on all possible numerical values in a given interval EX: length
Term
 Descriptive statistics
Definition
 Procedures that help us organize and describe data collected from either a sample or a population. What is there EX: average age, proportion of males and females in population
Term
 Inferential statistics
Definition
 the logic and procedures concerned with making predictions or inferences about a population from observations and analyses of a sample. saying something about the sample then saying how it reflects an entire population EX: average exam grade from 10 randomly drawn students in the class
Term
 Frequency distribution (definition and how to create them)
Definition
 frequency distribution- A table reporting the number of observations falling into each category of the variable how to create: 1- tally results 2- count frequencies
Term
 Proportion (p)
Definition
 a relative frequency obtained by dividing the frequency in each category by the total number of cases P=f/N    (expressed in 0.___ form) Proportions and percentages are relative frequencies.
Term
 Percentage (%)
Definition
 a relative frequency obtained by dividing the frequency in each category by the total number of cases (proportion) and multiplying by 100. (%) = p x 100 Proportions and percentages are relative frequencies.
Term
 Percentage Distributions
Definition
 A table showing the percentage of observations falling into each category of the variable.
Term
 Cumulative Frequency Distribution
Definition
 A distribution showing the frequency at or below each category (class interval or score) of the variable
Term
 Cumulative Percentage Distribution
Definition
 A distribution showing the percentage at or below each category (class interval or score) of the variable.
Term
 Rates
Definition
 A number obtained by dividing the number of actual occurrences in a given time period by the number of possible occurrences. EX: Number of people in U.S. prisons and jails incarceration rate= #incarcerated                            Population size *Be sure to look at day 3 notes at the last 2 slides*
Term
 Pie Chart
Definition
 A graph showing the differences in frequencies or percentages among categories of a nominal or an ordinal variable. The categories are displayed as segments of a circle whose pieces add up to 100 percent of the total frequencies. *When there are too many categories, the smaller categories can be reduced into a sort of "miscellaneous" category
Term
 Bar Graph
Definition
 A graph showing the differences in frequencies or percentages among categories of a nominal or an ordinal variable. The categories are displayed as rectangles of equal width with their height proportional to the frequency or percentage of the category. Ex: could be one bar column for "married people" or can display more by having a "married males" and "married females" columns right next to each  other
Term
 Statistical Map (def)  & Geographical Variations in Variables(def)
Definition
 Statistical map- displays dramatic geographical changes in a society Geographical Variations in Variables- like population distribution, voting patterns, crimes rates, or labor force participation.
Term
 Histogram
Definition
 a graph showing the differences in frequencies or percentages among categories of an interval-ratio variable. The categories are displayed as contiguous bars, with width proportional to the width of the category and height proportional to the frequency or percentage of that category.
Term
 Frequency Polygon
Definition
 A graph showing the differences in frequencies or percentages among categories of an interval-ratio variable. Points representing the frequencies of each category are placed above the midpoint of the category and are jointed by a straight line.
Term
 Time Series Chart
Definition
 A graph displaying changes in a variable at different points in time. It shows time (measured in units such as years or months) on the horizontal axis and the frequencies (percentages or rates) of another variable on the vertical axis.
Term
 Measure of Central Tendency
Definition
 Numbers that describe what is average or typical of the distribution You can think of this value as where the middle of a distribution lies.
Term
 Mode
Definition
 The category or score with the largest frequency (or percentage) in the distrubtion The mode can be calculated for variables with levels of measurement that are: nominal, ordinal, or interval-ratio
Term
 Median
Definition
 The score that divides the distribution into two equal parts, so that half the cases are above it and half below it. The median is the middle score, or average of middle scores in a distribution Can be calculated for ordinal or interval level variables Middle case= (N+1)/2
Term
 Mean
Definition
 The arithmetic average obtained by adding up all the scores and dividing by the total number of scores. Formula: Y bar= (sigma Y)/N Formula to calculate mean w/grouped scores: Y bar= (sigma (f)(Y))/N     Where (f)(y)= a score multiplied by its frequency
Term
 The measures that can be used with nominal, ordinal, and interval-ratio variables
Definition
 Nominal variable- the mode is the only measure that can be used. Ordinal variables- the mode and the median may be used. The median provides more information (taking into account the ranking of categories) Interval-ratio variables- the mode, median, and mean may all be calculated. The mean provides the most information about the distribution, but the median is preferred if the distribution is skewed.
Term
 Shapes of distributions
Definition
 Symmetrical- mean is about equal to median Skewed-a few extreme values on one side of the distribution shift the distribution Negatively- mean ex:children per household Positively- mean>median ex: income Bimodal- two distinct modes Multi-modal- more than 2 distinct modes *Refer to last slide on day 5 notes to view visual graphs
Term
 Measures of Variability
Definition
 Numbers that describe diversity or variability in the distribution Measures of variation reveal how far from the typical or central score that the distribution tends to vary
Term
 Index of Qualitative Variation (IQV)
Definition
 A measure of variability for nominal variables. It is based on the ratio of the total number of differences in the distribution to the maximum number of possible differences within the same distribution. IQV ranges 0-1. 0=no diversity.1=maximum diversity (evenlydistributed) IQV=K(1002 -Σf2)/1002(K-1) K=# of categories N =total # of cases in the distribution Σf2=the sum of all the squared frequencies or percentages
Term
 Range
Definition
 A measure of variation in interval-ratio variables. It's the difference between the highest (max) and the lowest (min) scores in the distrib.
Term
 Inter-Quartile Range (IQR)
Definition
 A measure of variation for interval-ratio data. It indicates the width of the middle 50 percent of the distribution and is defined as the difference between the lower and upper quartiles. Order scores high to low.(Q1 and Q3) IQR= Q3-Q1 Q3=75th percentile Q1=25th percentile
Term
 Box Plot
Definition
 Graphic device that visually presents the following elements: the range, the IQR, the median, the quartiles, the minimum (lowest value) and the maximum (highest value)
Term
 Variance (def) and Standard Deviation (def)
Definition
 Variance- measure of variation for interval-ratio variables; the average of the squared deviations from the mean.(S2Y equation) Standard Deviation- the square root of the variance.
Term
 Measures of variables that can use IQV or IQR
Definition
 Nominal variables- can only use IQV Ordinal variables- can calculate the IQV or the IQR Interval-ratio variables- can use IQV, IQR, or variance/standard deviation. Standard deviation provides most info, since it uses all the values in the distrib in its calc.
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