Lesson 4 Flashcards
It helps, describes and understands the features of specific data set by giving short summaries about the sample and measures of the data.
Descriptive Statistics
two basic categories of measures:
- Measures of Central Tendency
- Measures of Variability or Spread
Is all around us and everything that we do results in new data.
DATA
Are facts and figures collected, analyzed, and summarized for presentation and interpretation.
DATA
A characteristic or a quantity of interest that can take on different values.
Variable
Is a set of values corresponding to a set of variables.
Observation
Is the difference in a variable measured over observations (time, customers, items, etc.)
Variation
Types of Data
- Population and Sample Data
- Quantitative and Categorical Data
- Cross-Sectional and Time Series Data
- Sources of Data
A representative sample can be gathered by
random sampling
numeric and arithmetic operations such as addition, subtraction, multiplication, and division, can be performed on them
Quantitative Data
If arithmetic operations cannot be performed on the data
Categorical Data
are collected from several entities at the same, or approximately the same, point in time.
Cross-Sectional Data
are collected over several time periods.
Time Series Data
Two sources of data
- Experimental Study
- Non-experimental or Observational Study
It is often useful to create a frequency distribution for a data set.
1Frequency Distributions for Categorical Data
summary of data that shows the number of observations in each of several non-overlapping classes, typically referred to as bins, when dealing with distributions.
Frequency Distribution
2 creating distribution from data
- Frequency Distributions for Categorical Data
- Frequency Distributions for Quantitative Data
The three steps necessary to define the classes for a frequency distribution with quantitative data are:
- Determine the number of non-overlapping bins.
- Determine the width of each bin.
- Determine the bin limits.
A common graphical presentation of quantitative data. This graphical summary can be prepared for data previously summarized in either a frequency, a relative frequency, or a percent frequency distribution.
Histograms
A variation of the frequency distribution that provides another tabular summary of quantitative data is the blank, which uses the number of classes, class widths, and class limits developed for the frequency distribution.
Cumulative Distribution
