Module 2: Clean Data for More Accurate Insights Answers (Part 1: Q1–15)

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In this post, I provide accurate answers and detailed explanations for Module 2: Clean data for more accurate insights of Course 4: Process Data from Dirty to Clean – Google Data Analytics Professional Certificate.

Whether you’re preparing for quizzes or brushing up on your knowledge, these insights will help you master the concepts effectively. Let’s dive into the correct answers and detailed explanations for each question.

Here, we’ll walk through questions 1 to 15 with detailed explanations to support your learning.

To find answers to the remaining questions, check out the full module breakdown below:

  • Part 1 (Q1–15)
  • Part 2 (Q16–30)
  • Part 3 (Q31–46)

Test your knowledge on clean versus dirty data

Practice Quiz

1. Describe the difference between a null and a zero in a dataset.

  • A null represents a number with no significance. A zero represents the number zero.
  • A null indicates that a value does not exist. A zero is a numerical response. ✅
  • A null represents a value of zero. A zero represents an empty cell.
  • A null signifies invalid data. A zero is missing data.

Explanation:
A null means the data is missing or undefined, while a zero represents a valid numerical value indicating “nothing” or “none” in a specific context.

2. What are the most common processes and procedures handled by data engineers? Select all that apply.

  • Verifying results of data analysis
  • Developing, maintaining, and testing databases and related systems ✅
  • Transforming data into a useful format for analysis ✅
  • Giving data a reliable infrastructure ✅

Explanation:
Data engineers focus on:

  1. Database management: Developing and maintaining databases.
  2. Data transformation: Preparing raw data for analysis.
  3. Infrastructure reliability: Ensuring systems can handle data storage and processing efficiently.
    Verifying analysis results is typically a data analyst’s role, not a data engineer’s.

3. What are the most common processes and procedures handled by data warehousing specialists? Select all that apply.

  • Ensuring data is properly cleaned
  • Ensuring data is backed up to prevent loss ✅
  • Ensuring data is secure ✅
  • Ensuring data is available ✅

Explanation:
Data warehousing specialists focus on:

  1. Data backups: Protecting against data loss.
  2. Data security: Ensuring only authorized access.
  3. Data availability: Making data accessible for reporting and analysis.
    Cleaning data is typically the responsibility of data analysts or engineers.

4. A data analyst is cleaning a dataset. They want to confirm that users entered five-digit zip codes correctly by checking the data in a certain spreadsheet column. What would be most helpful as the next step?

  • Using the field length tool to specify the number of characters in each cell in the column ✅
  • Formatting the cells in the column as number
  • Changing the column width to fit only five digits
  • Using the MAX function to determine the maximum value in the cells in the column

Explanation:
The field length tool checks whether each zip code entry contains exactly five characters, ensuring accuracy.

  • Formatting cells as numbers or changing column width doesn’t validate input.
  • The MAX function is irrelevant for confirming zip code lengths.

Test your knowledge on data-cleaning techniques

Practice Quiz

5. Fill in the blank: Every database has its own formatting, which can cause the data to seem inconsistent. Data analysts use the _____ tool to create a clean and consistent visual appearance for their spreadsheets.

  • spellcheck
  • conditional formatting
  • clear formats ✅
  • autocorrect

Explanation:
The clear formats tool is used to remove all formatting from cells, ensuring that the data is displayed in a clean and consistent manner. This includes removing fonts, colors, borders, and other formatting styles, which can sometimes cause the data to appear inconsistent across a spreadsheet.

6. What is the process of combining two or more datasets into a single dataset?

  • Data validation
  • Data transferring
  • Data composition
  • Data merging ✅

Explanation:
Data merging is the process of combining datasets into a unified structure, enabling better analysis and integration. Other options like data validation or transferring are distinct tasks unrelated to merging.

7. Fill in the blank: In data analytics, _____ describes how well two or more datasets are able to work together.

  • alignment
  • compatibility ✅
  • suitability
  • agreement

Explanation:
Compatibility refers to the ability of datasets to align and work together effectively, such as matching formats, structures, or content for seamless integration and analysis.

Test your knowledge on cleaning data in spreadsheets

Practice Quiz

8. Describe the relationship between a text string and a substring.

  • A text string is a group of characters within a cell. A substring is a smaller subset of that text string. ✅
  • A text string is a row of data within a table. A substring is one cell within that row.
  • A text string is the list of attributes at the top of columns within a table. A substring is a single attribute within that list.
  • A text string is a column of data within a table. A substring is one cell within that column.

Explanation:
A text string refers to a sequence of characters, such as letters, numbers, or symbols, that are treated as text in a cell. A substring is a part or smaller portion of that larger text string. For example, in the string “Data Analysis,” the substring “Data” is a smaller part of the whole string.

9. A data analyst uses the COUNTIF function to count the number of times a value less than 5 occurs between spreadsheet cells A2 through A100. What is the correct syntax?

  • =COUNTIF(A2:A100,>5)
  • =COUNTIF(A2:A100,”>5″)
  • =COUNTIF(A2:A100,<5)
  • =COUNTIF(A2:A100,”<5″) ✅

Explanation:
The COUNTIF function requires a range and a condition. The condition must be enclosed in quotation marks when using comparison operators like <, >, or =. The correct syntax ensures that the function counts cells where the value is less than 5.

10. Fill in the blank: To remove leading, trailing, and repeated spaces in data, analysts use the ____ function.

  • LEFT
  • TRIM ✅
  • MID
  • RIGHT

Explanation:
The TRIM function removes all extra spaces from text, leaving only single spaces between words. It is particularly useful for cleaning data with unnecessary spaces that can cause errors or inconsistencies in analysis.

Module 2 challenge

Practice Quiz

11. As part of the data-cleaning process, a data analyst creates a rule to highlight any empty cells in a bright blue color. This is an example of data visualization.

  • True
  • False ✅

Explanation:
Highlighting empty cells visually represents missing data, which is a simple form of data visualization. It helps analysts quickly identify gaps in the dataset.

12. A data analyst at a nonprofit organization is working with the following spreadsheet, which contains member name data in column C. They want to divide this data using the underscore as a delimiter, so that first names are stored in one column and last names in another. Which tool should the analyst use?

  • Conditional formatting
  • Pivot table
  • SPLIT function ✅
  • MID function

Explanation:
The SPLIT function divides text into separate components based on a specified delimiter, such as an underscore (_). This allows analysts to separate first and last names into different columns.

13. Fill in the blank: When describing a SUM function, the _____ is =SUM(value 1 through value 2).

  • syntax ✅
  • standard
  • structure
  • script

Explanation:
Syntax is the correct format or “grammar” for writing a function.

14. You are working with the following selection of a spreadsheet:

In order to extract the five-digit postal code from Burlington, MA, what is the correct function?

  • =RIGHT(B3,5) ✅
  • =RIGHT(5,B3)
  • =LEFT(5,B3)
  • =LEFT(B3,5)

Explanation:
The RIGHT function extracts a specified number of characters starting from the right side of a text string. Here, it retrieves the last 5 characters of cell B3.

15. A data analyst in a human resources department is working with the following selection of a spreadsheet:

They want to create employee identification numbers (IDs) in column D. The IDs should include the year hired plus the last four digits of the employee’s Social Security Number (SS#). What function will create the ID 20093208 for the employee in row 5?

  • =CONCATENATE(A5!B5)
  • =CONCATENATE(A5*B5)
  • =CONCATENATE(A5+B5)
  • =CONCATENATE(A5,B5) ✅

Explanation:
Combines contents of cell A5 and B5 into one string.

That’s it for Part 1! Continue your learning journey with the next set of answers.

Next Part: Module 2: Clean Data for More Accurate Insights Answers (Part 2: Q16–30)

Part 2: Q16–30

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