# Descriptive Analytics I: Nature of Data, Statistical Modeling, and Visualisation - Statistical Modelling for Business Analytics

## 6 important questions on Descriptive Analytics I: Nature of Data, Statistical Modeling, and Visualisation - Statistical Modelling for Business Analytics

### What is the relationship between statistics an business analytics?

Statistics is an enabling tool to support evidence based managerial decision making.

### What are the main differences between descriptive and inferential statistics?

The main difference the data used.
Descriptive statistics is all about describing the sample data on hand.
Inferential statistics is about drawing inferences or conclusions about the characteristics of the population.

Remark: OLAP (online analytical processing) = Business Intelligence

### List and briefly define the central tendency measures of descriptive statistics.

Arithmetic mean: mean or average.
Median: measure of central value in a given data set. It is the number in the middle of a given data set arranged in asc. or desc. order. If the number is even, take the overage of the 2 middle values.
Mode: is the observation that occurs most frequently. most useful in data sets with a small number of unique values.

In summary:
Use mean if no outliers
Use median if outliers
Use mode when the data is nominal.
Best proactics: use all 3 together!

### What is the box-and-whiskers plot?

Is a graphically illustration of several descriptive statistics about a given data set. Horizontal or Vertical (= most common used). Used to illustrate both, centrality and dispersion.
The dispersion: the density of the data within the middle half, drawn as a box between the 1st and the 3rd quartile.

### What are the 2 most commonly used shape characteristics to describe a data distribution?

Skewness (scheefheid):  measure of asymmetrie. 1 peak.
S>0: mean < median, tail on the right.
S<0: mean > median, tail on the left.
Kurtosis: characterizing the peak/tall/skinny nature of the distribution. K>0 peaked distribution, K<0 flat distribution

### How to Calculate Descriptive Statistics in Microsoft Excel?

Technology Insights 2.1 p 108.
Statistics functions as part of the analytics ToolPak. Excel 2016.

The question on the page originate from the summary of the following study material:

• A unique study and practice tool
• Never study anything twice again
• Get the grades you hope for
• 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.