Exam 1

Question 1

Column Filter Node

Answer 1

Used to select columns for analysis.

oRight click -> configure -> choose columns you want

Question 2

Statistics Node

Answer 2

Shows univariate statistics and some limited diagrams.

Question 3

Missing Values Node

Answer 3

Removes rows with missing values.

Missing Value -> Configure -> Column Settings -> Remove Row

Question 4

Row Filter Node

Answer 4

o Filter to see only one type (Positions-> Catcher)
o Filter to see anything that contains Pitch. * Is a wild character – Must select contains wild card Box
o Filter to retrieve a range
-Catchers between 25-35, need 2 separate nodes (cant combine)

Question 5

Nominal Value Row Filter Node

Answer 5

Lets you pick one nominal column and filter by selected categories in that variable.
-ex: (Positions-> Catcher, Outfielder, Shortstop)

Question 6

Types of Missing Values

Nominal Categorical

Answer 6

1) Missing completely at random (MCAR)

2) Missing not at random (MNAR)

Question 7

How do you handle missing data?

Answer 7

1)Study the reason for missing
The data could be missing because of MNAR.
2)Ignore it (still keep the record in data set)
This may not be a wise decision because some DM techniques are very sensitive to missing data.
3)Pairwise deletion of rows: an observation with missing value for variable X is removed from statistics (such as correlation matrix) involving the variable X. It is not removed from statistics not involving X.