K201 MIS Keyword Exam 2

categorical data

labels or names used to identify an attribute of each element. (Nominal or ordinal, numeric or nonnumeric)

quantitative data

numeric values that indicate how much or how many of something.(interval or ratio scale)

Frequency distribution calculations:

Frequency

Relative frequency

Percent frequency

bar chart

A graphical device for depicting categorical data that have been summarized in a frequency, relative frequency, or percent frequency distribution.(Column/Bar Chart in Excel)

pie chart

A graphical device for presenting data summaries based on subdivision of a circle into sectors that correspond to the relative frequency for each class.

Summarizing Categorical Data

Summary TableObjective is to: summarize the frequency of each category Excel function used: COUNTIF

Frequency Distribution ~ Formula:=COUNTIF(range, category)

Relative Frequency Distribution ~ Formula:relative frequency * 100

Bar Chart

Pie Chart

Quantitative data frequency distribution steps

Number of classes

Width of classes

Class limits

class midpoint

value halfway between the lower and upper class limits

Relative frequency formula for a quantitative variable

frequency/n

dot plot

graphical device that summarizes data by the number of dots above each data value on the horizontal axis

histogram

A graphical display of a frequency distribution, relative frequency distribution, or percent frequency distribution of quantitative data constructed by placing the class intervals on the horizontal axis and the frequencies, relative frequencies, or percent frequencies on the vertical axis.

histogram skewness types

symmetric, moderately skewed left, moderately skewed right highly skewed right

symmetric

left tail is the mirror image of the right tail(heights of people)

moderately skewed left

longer tail to the left(exam scores)

moderately skewed right

longer tail to the right(housing values)

highly skewed right

very long tail to the right(executive salaries)

cumulative frequency distribution

A tabular summary of quantitative data showing the number of data values that are less than or equal to the upper class limit of each class.

Last entry: total number of observations

cumulative relative frequency distribution

A tabular summary of quantitative data showing the fraction or proportion of data values that are less than or equal to the upper class limit of each class.

Last entry: 1.00

cumulative percent frequency distribution

A tabular summary of quantitative data showing the percentage of data values that are less than or equal to the upper class limit of each class.

Last entry: 100% or 100

stem-and-leaf display

A graphical display used to show simultaneously the rank order and shape of a distribution of data.

summarizing quantitative data(1)

Frequency Distribution - has 3 steps. Use Excel's Pivot Tables to construct Frequency Distribution.

summarizing quantitative data(2)

Relative and Percent Frequency Distributions

summarizing quantitative data(3)

Dot Plot - Horizontal axis shows the range of data values.Then each data value is represented by a dot placed above the axis.

summarizing quantitative data(4)

Histogram - Variable of interest is placed on the horizontal axis. A rectangle is drawn above each class interval with its height corresponding to the interval's frequency, relative frequency, or percent frequency. No natural separation between rectangles.

summarizing quantitative data(5)

Cumulative Distributions. Two Types

summarizing quantitative data(6)

Stem-and-Leaf Display - shows both the rank order and shape of the distribution of the data. Similar to histogram on its side, BUT has the advantage of showing the actual data values. Each line (row) in the display is referred to as a stem. Each digit on a leaf is a data value.

crosstabulation

A tabular summary of data for two variables. The classes for one variable are represented by the rows; the classes for the other variable are represented by the columns.

crosstabulation(2)

row or column percentages

Can provide additional insight about the relationship between the two variables. Simpson's Paradox - the reversal of conclusions based on aggregate and unaggregated data

scatter diagram

A graphical display of the relationship between two quantitative variables. One variable is shown on the horizontal axis and the other variable is shown on the vertical axis.

trendline

A line that provides an approximation of the relationship between two variables.

Scatter diagrams and trendlines: Are useful in exploring the relationshipsbetween 2 Quantitative variables.

Scatter diagram relationships

Positive(both increase)

Negative(increase, decrease)

No apparent(flat)

side by side bar chart

A graphical display for depicting multiple bar charts on the same display.

stacked bar chart

A bar chart in which each bar is broken into rectangular segments of a different color showing the relative frequency of each class in a manner similar to a pie chart.

data visualization

describes the use of graphical displays to summarize and present information about a data set. The goal is to communicate as effectively and clearly as possible the key information about the data.

data dashboard

Widely used data visualization tool that provides timely, summary information in an easy to read and interpret format. Organizes and presents KPIs (Key Performance Indicators) used to monitor an organization or process.

Statistics

the art and science of collecting, analyzing, presenting and interpreting data

data

the facts and figures collected, analyzed, and summarized for presentation and interpretation

data set

all the data collected in a particular study

elements

the entities on which data are collected(ROW)

entity

an object, individual, or unit about which data are collected.(ROW)

variable

a characteristic of interest for the elements(COLUMN)

observation

the set of measurements obtained for a particular element(ROW)

scale

determines the amount of information contained within the data. Indicates the type of appropriate statistical analysis that can be performed.

Scales of measurement categorical

nominal, ordinal

nominal

scale of measurement for a variable when the data are labels or names used to identify an attribute of an element.(nonnumeric or numeric).

WTO Status

ordinal

scale of measurement for a variable if the data exhibit the properties of nominal data and the order or rank of the data is meaningful(nonnumeric or numeric).

Class rank of a student

Scale of measurement quantitative

interval, ratio

Interval

scale of measurement for a variable if the data demonstrate the properties of ordinal data and the interval between values is expressed in terms of a fixed unit of measurement.(always numeric)

SAT SCORES

ratio

scale of measurement for a variable if the data demonstrate all the properties of interval data and the ratio for two values is meaningful.(always numeric)

Melissa's college record shows 36 credit hours earned,while Kevin's record shows 72 credit hours earned. Kevin has twice as many as Melissa.

Data classifications

Categorical, quantitative, cross-sectional, time series data

Cross-sectional data

data collected at the same or approximately the same point in time

Per capita GDP

time series data

data collected over several time periods

U.S average price per gallon of conventional regular gas between 2012 and 2018

Data variable types

categorical, quantitative

categorical variable

a variable with categorical data, Labels or names used to identify an attribute of each element; grouped by category(QUALITATIVE)

quantitative variable

a variable with quantitative data, How many or how much, always numeric

quantitative data

discrete, continuous

Discrete

if measuring how many(exact figures you can count)

continuous

if measuring how much(measurable values representing a range of information)

data sources

existing data sources:

Internal company records

Business database services

Government agencies

Industry associations

Special-interest organizations

Internet: data we create

Statistical Studies

observational studies

no attempt is made to control or influence the variables of interest. Observe what is happening & record data only

Surveys, public opinion polls

experimental studies

variable of interest is first identified, then one or more variables are identified and controlled so that data can be obtained about how they influence the variable of interest

Pharmacy companies test new drugs by giving different doses to people and monitoring the effects.

descriptive statistics

Data that are summarized and presented in a form that is easy for people to understand

descriptive statistics summaries of data may be:

tabular, graphical, and numerical

mean(average)

demonstrates a measure of the central tendency(location) of the data for a variable

statistical processes

Statistical inference(data to make hypotheses about population characteristics)

Census(survey collects data on an entire population)

Sample survey(collect data on a sample)

element sizes

population, sample

statistics analysis software

Excel

analytics

scientific process of transforming data into insight for making better decisions

analytics technique categories

descriptive, predictive, prescriptive

descriptive analytics

A set of analytics techniques that describe what has happened in the past

predictive analytics

set of analytical techniques that use models constructed from past data to predict the future or assess the impact of one variable on another

Prescriptive Analytics

set of analytical techniques that yield a best course of action

big data

A set of data that cannot be managed, processed, or analyzed with commonly available software in a reasonable amount of time.(great volume, high velocity, wide variety)

data warehousing

Process of capturing, storing, and maintaining the data

data mining

The process of using procedures from statistics and computer science to extract useful information from extremely large databases.

data mining major applications

made by companies with a large amount of data

data mining model reliability

careful validation of results and extensive testing is important

Ethical guidelines for statistical practice was developed by

the American Statistical Association

REMEMBER THIS

observation = elements = entities

Data values

variables x elements/observations/entities