Data Mining test
What are the 3 central tendencies - answerMean, Medium, Mode
Define Desperation - answerdegree to which numerical data tends to spread
What does OLTP and OLAP and define - answerOnline Transaction Processing - day to
day transaction
Online Analytical Processing - tool provided by data warehouse management system
for data analysis and decision making
What are 4 OLAP operates and what do they do - answerDrill up - summarises data
Drill down - from summary to more detailed data
Slice & Dice - project & select
Pivot - re-orientate cube
Difference between data mining and OLAP - answerOLAP - tells whats happening to
data
DM - tells whats happening to data, why its happening and can predict future
What the purpose of pre-processing - answerTo deal with
-Noisy data
-Incomplete data
-Inconsistent data
What is noisy data and what causes it - answerRandom errors, outliers
faulty data collection equipment, human/computer input error
What is incomplete data and what causes it - answerData missing attributes or missing
attributes of interest
unknown or not considered important at data collection, equipment malfunction
What is inconsistent data and what causes it - answerData containing discrepancies in
naming convention, data domain or format
-different sources
-changes in strategy of data warehousing
-functional dependencies violation
Purpose of data cleaning and what it involves (4) - answerremoving noisy data &
correcting inconsistencies
-filling in missing values
-smoothing noisy data
