Unit 5 - Statistical Analysis for Descriptive Statistics (Review for IT-312 QUIZ 1)

Descriptive Analytics

is a statistical technique used to search and summarize historical data to identify patterns or meanings.

Descriptive Analytics

It is an initial stage in data processing that creates a summary of historical data to obtain useful information and possibly prepare the data for further analysis.

Descriptive Analytics

Examination of data or content, usually manually performed, to answer the question "What happened?" (or What is happening?)

Descriptive Analytics

characterized by traditional business intelligence (BI) and visualizations such as pie charts, bar charts, line graphs, tables, or generated narratives

Discrete Attribute

Types of Data

has a finite or countably infinite set of values, which may or may not be represented as integers.

Continuous Attribute

Types of Data

Are typically represented as floating-point variables. The terms numeric attribute and continuous attribute are often used interchangeably in the literature.

Discrete Attribute

Types of Data

Basically countable whole numbers or zero. Mainly used for counting.

Continuous Attribute

Types of Data

Basically measurable numbers (Any number in A to B) that are in decimal form. Mainly used for measuring.

Measures of Central Tendency

BASIC STATISTICAL DESCRIPTION OF DATA

can be defined as a descriptive statistical method which describes or shows the center value in a dataset.

Measures of Central Tendency

BASIC STATISTICAL DESCRIPTION OF DATA

It can be referred to as the measure of central location where most values in a distribution fall.

Mean (Average)

BASIC STATISTICAL DESCRIPTION OF DATA

Representation of the sum of all values in a dataset divided by the total number of the values.

Median

BASIC STATISTICAL DESCRIPTION OF DATA

simply the middle value in a dataset. In the case where the dataset has even number of values, the ___________ of that dataset is the average or mean of the two middle values.

Mode

BASIC STATISTICAL DESCRIPTION OF DATA

as the most recurrently occurring value in a dataset. Some dataset may contain multiple ________ while in some may not have any _______ at all. It is a measure of central tendency with largest frequency* in a table.

Long Left Tails

Rules for Skewness

In a negative skew, what do you call its tail?

Long Right Tail

Rules for Skewness

In a positive skew, what do you call its tail?

Normal Distribution

It is a distribution that contains the measures of central tendency in the middle, with symmetrical sides, and an asymptotic tail.

Left-Skewed (Negative Skewness)

In a skewed data set, what type of skewness contains the following order:

Mean(lowest), Median, Mode(Highest)

Right-Skewed (Positive Skewness)

In a skewed data set, what type of skewness contains the following order:

Mode, Median, Mean where:

Mean > Median > Mode

Mode

What is the best measure of central tendency of a Nominal Variable?

Median

What is the best measure of central tendency of an Ordinal Variable?

Mean

What is the best measure of central tendency of an Interval/Ratio variable that is not skewed?

Median

What is the best measure of central tendency of an Interval/Ratio variable that is skewed?

Measures of Dispersion or Variability

Refers to how scattered a group of data is. Shows how much the data differs or vary from the average distribution.

Variability and dispersion

Are some of the terms that describes how spread out a certain distribution is.

Absolute measure of dispersion

Categories of Measures of Variability or Dispersion

A measure which expresses the scattering of observation in terms of distances

Relative measure of dispersion

Categories of Measures of Variability or Dispersion

is used for comparing distributions of two or more dataset and for unit free comparison.

Range

The simplest variability measure of and dispersion to calculate is the _________. It is easy to calculate and easy to understand. It just simply the difference between the highest and the lowest score in a dataset.

Interquartile Range

Measure of dispersion or variation based on distributing a data set into quartiles.

Interquartile Range (Quartiles)

_________ means dividing the dataset into four equal parts. These values will be separated in parts called the first, second, and third quartiles; and they are denoted by Q1, Q2, and Q3, respectively

Variance

An average of the squared differences of the scores from the computed mean.

Variance

is a measurement of how far each number in the dataset is from the mean and from every other number in the dataset.

Standard Deviation

is a measure of dispersion or variation that measures the difference between each data point and the mean.

Smaller

Standard Deviation

When the values in a dataset are closely distributed, the standard deviation is _________.

Larger

Standard Deviation

But when the values in a data set are scattered, the standard deviation is __________ for the reason that the distance is greater.

Percentiles

is a number where a certain percentage of scores fall below that number.

For example, a 90th ___________ marks the spot where 90% of values fall below that cut-off point.

Quartiles

divide a rank-ordered data set into four equal parts. The values that divide each part are called the first, second, and third quartiles; and they are denoted by Q1, Q2, and Q3, respectively.