quiz Flashcards
Why is the role of the accountant chaning?
Technology has taken over many activities historically done by accountants
Which of the following is not a basic characteristic of a data warehouse?
- Relational
- Real-time
- Time-variant
- Nonvolatile
Real-time
Which of the following is not a category of SQL commands?
- TCL
- SCL
- DCL
- DDL
SCL
What does the robustness of a data mining method refer to?
Its ability to overcome noisy data to make somewhat accurate predictions
How is the precision calculated?
Precision is the ratio of correctly classified positive observations to the total predicted positive observations
TP / (TP+FP)
How is the recall calculated?
Recall, also known as sensitivity or true positive rate, is the ratio of correctly classified positive observations to all the observations in the actual class.
TP / (TP+FN)
How is the accuracy calculated?
Accuracy is the ratio of correctly classified observations (both positive and negative) to the total observations
(TP+TN) / total observations
What does it mean when a database is time-variant?
the ability to track and manage changes to the data over time. The data warehouse not only stores current data but also historical data.
What is nominal data?
Nominal data represents categories with no intrinsic ordering or ranking.
EG types of fruit
What is interval data?
Interval data is numerical data with meaningful intervals between values, but no true zero point.
EG celcius
What is ordinal data?
Ordinal data represents categories with a meaningful order, but the intervals between categories are not necessarily equal.
EG movie ratings
What is ratio data?
Ratio data is numerical data with a meaningful zero point, allowing for both differences and ratios to be calculated.
EG weight in kg
Would a K-means clustering algorithm always show the same results for a given set of input data if we keep k and all other parameters contsant?
No, because the initial selection of cluster center points is random.
In text mining, stemming is the process of
Reducing multiple words to their base or root
In text mining, what are 3 methods used to reduce the size of a sparse matrix?
- Using a domain expert
- Using singular value decomposition (SVD)
- Eliminating rarely occurring terms.
