Deck 7: Data Mining: Cluster Analysis: More on the While Loop; Parrallel Lists

Question 1

The equation d = X&It;sub>2&It;/sub> - X&It;sub>1&It;/sub> is used to find:

A) Euclidean distance.
B) clustering.
C) a data mine.
D) the Pythagorean theorem.

Answer 1

A

Question 2

A(n) ____ is defined as the mean of a collection of data points.

A) point collection
B) cluster
C) Euclid
D) centroid

Answer 2

D

Question 3

In the K-means algorithm, the number of clusters is represented by:

A) c.
B) k.
C) the absolute value of X&It;sub>2&It;/sub> - X&It;sub>1&It;/sub>.
D) a star.

Answer 3

B

Question 4

Case Study 1:
1. def readFile(filename ):
2. with open(filename , "r") as dataFile
3. dataDict = {}
4.
5. key = 0
6. for aLine in dataFile:
7. key = key + 1
8. score = int(aLine)
9.
10. dataDict[key] = [score]
11.
12. return dataDict
-Refer to the session in the accompanying Case Study 1. What happens in Line 10?

A) The score is entered in the dictionary associated with the key.
B) The line is read from the file.
C) The key is computed.
D) The file is opened.

Question 5

Case Study 1:
1. def readFile(filename ):
2. with open(filename , "r") as dataFile
3. dataDict = {}
4.
5. key = 0
6. for aLine in dataFile:
7. key = key + 1
8. score = int(aLine)
9.
10. dataDict[key] = [score]
11.
12. return dataDict
-Refer to the session in the accompanying Case Study 1. What is the purpose of the program code [score]?

A) It restricts the dictionary score to only hold a list.
B) It allows for multidimensional data points.
C) It uses the absolute value of score.
D) It places the variable score in a cluster.

Question 6

What best describes the type of iteration that is shown in the code below?
For num in [1, 2, 3, 4, 5]:
Print("hello")

A) Definite
B) Indefinite
C) Nested
D) Numeric

Question 7

What Python statement is used to create indefinite iteration?

A) for
B) while
C) if
D) range

Question 8

Case Study 2:
1. total = 0
2. aNum = 1
3. while aNum &It;= 10:
4. total = total + aNum
5. aNum = aNum + 1
6. print(total)
-Refer to the session in the accompanying Case Study 2. Which line represents the initialization of the loop condition?

A) 1
B) 2
C) 3
D) 5

Question 9

Case Study 2:
1. total = 0
2. aNum = 1
3. while aNum &It;= 10:
4. total = total + aNum
5. aNum = aNum + 1
6. print(total)
-Refer to the session in the accompanying Case Study 2. Which line checks the condition of the loop?

A) 1
B) 2
C) 3
D) 5

Question 10

What is the problem with the loop shown below? 1. total = 0
2) aNum = 1
3) while aNum &It;= 10:
4) total = total + aNum
5) print(total)

A) There is no initialization statement.
B) The condition is not checked.
C) It is a definite loop.
D) It is an infinite loop.

Question 11

Latitude values run north-south with zero latitude located at the equator. The north pole of the globe is +90, and the south pole is:

A) −180.
B) −90.
C) 0.
D) +90.

Question 12

Case Study 3:
>>> aLine = next(csvReader)
>>> aLine
['3.7', '2006/10/18', '05:34:15', '62.326', '-151.224', '85.9', 'CENTRAL ALASKA']
>>> aLine[3]
>>> ???
>>> aLine[6:]
>>> ???
-Refer to the session in the accompanying Case Study 3. What is printed for aLine[3]?

A) '3.7'
B) '62.326'
C) '-151.224'
D) ['CENTRAL ALASKA']

Question 13

Case Study 3:
>>> aLine = next(csvReader)
>>> aLine
['3.7', '2006/10/18', '05:34:15', '62.326', '-151.224', '85.9', 'CENTRAL ALASKA']
>>> aLine[3]
>>> ???
>>> aLine[6:]
>>> ???
-Refer to the session in the accompanying Case Study 3. What is printed for aLine[6:]?

A) '3.7'
B) '62.326'
C) '-151.224'
D) ['CENTRAL ALASKA']

Question 14

What method is used to set a background image for a turtle screen?

A) bgpic
B) Screen
C) bg
D) screensize

Question 15

Once the turtle has been directed to the proper location, what method will plot a point using the current tail color?

A) point
B) draw
C) dot
D) color

Question 16

One of the most important steps in the cluster analysis algorithm is to classify data points with regard to their similarity to other data points.

Question 17

When using the K-means algorithm, points will always remain in the same cluster even after several iterations.

Question 18

A for loop is used to create indefinite iteration.

Question 19

Longitude values run west-east, with the zero being the prime meridian, an imaginary line that runs north-south through Greenwich, England.

Question 20

The process of "visualizing" data can be quite useful, especially if one is looking for hard-to-see relationships that may not be readily apparent from long lists of data.

Question 21

Match each definition with its phrase.
-Allows loop body statements to be executed until a condition becomes false.

A) while loop
B) for loop
C) infinite loop

Question 22

Match each definition with its phrase.
-Allows a group of statements to be repeated, once for each value in a sequence.

A) while loop
B) for loop
C) infinite loop

Question 23

Match each definition with its phrase.
-A loop that never stops.

A) while loop
B) for loop
C) infinite loop

Question 24

What is data mining? Provide an example of an application in which data mining would be useful.

Question 25

How is the distance between two points calculated?

Question 26

What is a centroid and what role does it play in cluster analysis?

Question 27

What are the basic steps in the K-means algorithm?

Question 28

How do you retrieve a random data value in Python?

Question 29

Explain how the while loop works in Python.

Question 30

One of the weaknesses of the K-means cluster analysis algorithm is that the clusters can become empty. Describe how this problem occurs and its effect.

Question 31

One of the weaknesses of the K-means cluster analysis algorithm is that the clusters can become too large. Describe how this problem occurs and a possible solution.