additional Flashcards
Definition of statistics
the art and science of collecting, analyzing, presenting and interpreting data
the term Statistics refers to
numerical facts such as averages, medians, percentages and maximums that help us understand a variety of business and economic situations
Data
the facts and figures collected, analyzed and summarized for presentation and interpretation
data set
all the data collected in a particular study
Elements
entities on which data are collected
Variable
characteristic of interest fro the elements
Observation
set of measurements obtained for a particular element
What are the scales of measurement
- Nominal scale
- Ordinal Scale
- Interval Scale
- Ratio Scale
What is the nominal scale
the data for a variable consists of labels or names used to identify an attribute of the element
What is ordinal scale
the data exhibits the properties of nominal data and addition, the order or rank of the data is meaningful
What is interval scale
the data have all the properties of interval data and the ratio of two values is meaningful
The statistical method appropriate for summarizing data depends on whether the data are
categorical or quantitative
categorical data
data that can be groped by specific categories
- uses either the nominal or ordinal scale of measurement
Quantitative data
uses numeric values to indicate how much or how many
- uses either the interval or ratio scale of measurement
Cross-sectional data
data collected at the same or approximately the same point in time
Time series data
data collected over several time periods
An observation is the set of measurements obtained for each element in a data set. Hence, the number of observations is always the same as
the number of elements
An observation is the set of measurements obtained for each element in a data set. Hence, the number of observations is always the same as
the number of elements
Qualitative data can be
Discrete (finite)
Continuous (time/ weight) no seperation b/w possible data values
Descriptive statistics
summaries of data which may be tabular, graphical or numerical
Statistical inference
the process of using data obtained from a sample to make estimates or test hypotheses about the characteristics of a population
Data mining
deals with methods for developing useful decision-making information form large databases
- very useful for companies with strong consumer focus such as retail business, financial organizations, and communication companies
- the process of using procedures form statistics and computer science to extract useful information from extremely large databases
descriptive statistics
tabular, graphical, and numerical summaries of data
Data visualization
used to describe the use of graphical displays to summarize and present information about a data set