# Shared Flashcard Set

## Details

Introduction to Statistics
n/a
59
Economics
09/24/2012

Term
 Statistics
Definition
 Art and science of collecting, analyzing, presenting, and interpreting data
Term
 Data
Definition
 Facts and figures collected, analyzed, summarized for interpretation and presentation
Term
 Elements
Definition
 Entities on which data are collected
Term
 Variable
Definition
 Characteristic of interest for the elements
Term
 Nominal Scale
Definition
 When the data for a variable consists of labels or names used to identify an attribute of the element
Term
 Ordinal Scale
Definition
 Scale of measurement for a variable Example: excellent, poor, good on a survey
Term
 Interval Scale
Definition
 Scale of measurement used if the data have all the properties of ordinal data and the interval between values is expressed in terms of a fixed unit of measure. Always numeric. Example: College Admission SAT scores
Term
 Ratio Scale
Definition
 Scale used if the data have all the properties of interval data and the ratio of two values is meaningful Example: distance, height, time
Term
 Categorical Data
Definition
 Data grouped into specific catergories
Term
 Quantitative Data
Definition
 Data that uses numeric values
Term
 Categorical Variable
Definition
 Variable that uses categorical data
Term
 Quantitative Variable
Definition
 Variable that uses quantitative data
Term
 Cross-sectional data
Definition
 Data collected at the same or approximately the same point in time
Term
 Time Series Data
Definition
 Data collected over several time periods
Term
 Descriptive Statistics
Definition
 Summaries of data, which may be tabular, graphical, or numerical
Term
 Population
Definition
 The larger group of elements in a particular study
Term
 Sample
Definition
 Smaller group of the population; selected randomly
Term
 Census
Definition
 Process of conducting a survey to collect data for the entire population
Term
 Statistical Inference
Definition
 Statistical process that uses data from a sample to make estimates and test hypotheses about the characteristics of a population
Term
 Data mining
Definition
 Deals with methods for developing useful decision-making information from large data bases
Term
 Frequency Distribution
Definition
 A tabular summary of data showing the number (frequency) of items in each of several nonoverlapping classes
Term
 Relative Frequency Distribution
Definition
 Tabular summary showing relative frequency Relative Frequency=F/n
Term
 Percent Frequency Distribution
Definition
 Summarizes the percent frequency of the data for each class. Relative Frequency times 100=Percent frequency
Term
 Bar Chart
Definition
 Graphical device depicting categorical (qualitative) data
Term
 Pie Chart
Definition
 Another graphical device presenting relative frequency and percent frequency for categorical data
Term
 Class midpoint
Definition
 Value halfway between the lower and upper class limits
Term
 Dot plot
Definition
 One of the simplest graphical summaries. Horizontal axis shows range for data. Each value is represented by dot above.
Term
 Histogram
Definition
 Similar to a Bar chart but represents quantitative data rather than qualitative
Term
 Cumulative Frequency Distribution
Definition
 Shows the number of data items with values less than or equal to the upper class limit of each class
Term
 Cumulative Relative Frequency Distribution
Definition
 Shows the proportion of data items
Term
 Cumulative Percent Frequency Distribution
Definition
 Shows the percentage of data items with values less than or equal to the upper limit of each class
Term
 Ogive
Definition
 A graph of cumulative distribution. Data values on horizontal axis. Frequencies of frequency percentages on vertical axis.
Term
 Explanatory Data Analysis
Definition
 Consists of simple arithmetic and easy-to-draw graphs that can be used to summarize data quickly
Term
 Stem and Leaf display
Definition
 Can be used to show both the rank order and shape of a data set simultaneously
Term
 Cross tabulation
Definition
 Tabular summary of data for two variables
Term
Definition
 The reversal of conclusions bases on aggregate and unaggregated data
Term
 Scatter Diagram
Definition
 Graphical presentation of the relationship between two quantitative variables
Term
 Trendline
Definition
 Line that provides approximation of the relationship between quatitative variables
Term
 Sample Statistics
Definition
 Measures that are computed for data from a sample
Term
 Population Parameters
Definition
 Measures are computed for data from a population
Term
 Point Estimator
Definition
 A sample statistic is referred to as the point estimator of the corresponding population parameter
Term
 Median
Definition
 Measure of central location. Value in the middle
Term
 Percentile
Definition
 Provides info about how the data are spread over the interval from the smallest to largest value
Term
 Quartiles
Definition
 Division points after dividing data distribution into four parts
Term
 Range
Definition
 Largest value minus smallest value
Term
 Interquartile range (IQR)
Definition
 Difference between the third quartile (Q3) and the first quartile (Q1)
Term
 Variance
Definition
 Measure of variability that utilizes all the data. Based on the difference between the value of each observation and the mean
Term
 Standard Deviation
Definition
 The positive square root of the variance
Term
 Coefficient of Variation
Definition
 Standard deviation divided by the mean multiplied by 100.
Term
 Skewness
Definition
Term
 Skewness
Definition
 Important numerical measure of the shape of a distribution
Term
 Chebyshev's Theorem
Definition
 At least (1-1/z^2) of the data values must be within z standard deviations of the mean, where z is any value greater than 1
Term
 Empirical Rule
Definition
 For data having a bell-shaped distribution: -Approx. 68% of values will be within one standard deviation of the mean -Approx. 95% will be within two standard deviations -Almost all values will be within three standard deviations of the mean
Term
 Outliers
Definition
 Extreme values
Term
 Five-number summary
Definition
 Following five numbers are uesd to summarize the data: 1. Smallest value 2. First Quartile (Q1) 3. Median (Q2) 4. Third quartile (Q3) 5. Largest value
Term
 Box plot
Definition
 Graphical summary of data that is based on five-number summary
Term
 Covariance
Definition
 Descriptive measure of the linear association between two variables
Term
 Correlation Coefficient
Definition
 Measure of the relationship between two variables that is not affected by the units of measurement for x and y
Term
 Weighted Mean
Definition
 xi=value of observation wi=weight of observation   x=(wi)(xi)/wi
Supporting users have an ad free experience!