Question 12 (3 points)

The map phase of MapReduce is the data aggregation phase that aggregates results from multiple reducers.

Question 12 options:

	1) True
	2) False

Question 13 (3 points)

Schema-on-write refers to the practice of defining database structure (e.g., data types, relationships, constraints, etc.) when the data is read from the database.

Question 13 options:

	1) True
	2) False

Question 14 (3 points)

Excel's data model can store more data than Excel's worksheets.

Question 14 options:

	1) True
	2) False

Question 15 (3 points)

Hadoop by default stores data in its raw format on multiple machines called data nodes.

Question 15 options:

	1) True
	2) False

Question 16 (3 points)

Sqoop can be used to transfer data from a relational database to Hadoop's Hive or HBase database.

Question 16 options:

	1) True
	2) False

Question 17 (3 points)

HDFS is a data processing component of Hadoop, while MapReduce is the data storage component.

Question 17 options:

	1) True
	2) False

Question 18 (3 points)

Pig, Spark and Hive are among the components in Hadoop ecosystem.

Question 18 options:

	1) True
	2) False

Question 19 (3 points)

For a "client" program (such as Excel) to retrieve data from Hadoop, it must first contact the NameNode before it knows where the data is located.

Question 19 options:

	1) True
	2) False

Question 20 (3 points)

HDFS is used to start or stop hadoop ecosystem services.

Question 20 options:

	1) True
	2) False

Question 21 (3 points)

By default, Hadoop stores a copy of the data at three NameNodes.

Question 21 options:

	1) True
	2) False

Question 22 (3 points)

Files on HDFS can be edited directly just like your normal file system on Windows or Mac.

Question 22 options:

	1) True
	2) False

Question 23 (3 points)

NameNode is used to store user data files.

Question 23 options:

	1) True
	2) False

Question 24 (3 points)

The secondary NameNode is the exact copy of the primary NameNode that can be directly restored when the primary NameNode fails.

Question 24 options:

	1) True
	2) False

Question 25 (3 points)

In HDFS, filesystem information is stored in a file called fsimage, but all changes to the filesystem are not made to fsimage immediately. Instead, they are recorded in the edit log.

Question 25 options:

	1) True
	2) False

Question 26 (3 points)

If a dataset contains the following 4 columns: recordID, branchNo, sales, year. In order to show the average sales by year, the MAP phase must create key/value pairs with year being the key and sales being the value to form the (key, value) pairs.

Question 26 options:

	1) True
	2) False