CompTIA DA0-001 Online Practice Questions and Exam Preparation

CompTIA DA0-001 Online Questions & Answers

• Question 201:

  A development company is constructing a new Init in its apartment complex. The complex has the following floor plans:

  

  Using the average cost per square foot of the original floor plans. which of the following should be the price of the Rose Init?

  A. $640,900
  B. $690,000
  C. $705,200
  D. $702,500
  D. $702,500

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  Explanation

  The correct answer is

  D. $702,500. To find the price of the Rose unit, we need to use the average cost per square foot of the original floor plans. The average cost per square foot is calculated by dividing the price by the square footage of each unit type. Using the data from the table, we can do the following: Jasmine: $345,000 / 1,000 = $345 per square foot Orchid: $525,000 / 2,000 = $262.5 per square foot Azalea: $375,000 / 1,500 = $250 per square foot Tulip: $450,000 / 1,800 = $250 per square foot The average cost per square foot of the original floor plans is the mean of these four values, which is ($345 + $262.5 + $250 + $250) / 4 = $276.875 per square foot. To find the price of the Rose unit, we need to multiply the average cost per square foot by the square footage of the Rose unit. The Rose unit has a square footage of 2,535, according to the table. Therefore, the price of the Rose unit is $276.875 x 2,535 = $702,421.875. Rounding to the nearest whole number, we get $702,500 as the price of the Rose unit.

• Question 202:

  A financial institution is reporting on sales performance to a company at the account level. Due to the sensitive nature of the government the does il with, some account information is not shown.

  Which of the following fields should be masked?

  A. Sales volume
  B. Start date
  C. Product name
  D. Customer name
  D. Customer name

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  Explanation

  Customer name is the field that should be masked, because it contains sensitive information that could identify the government accounts that the financial institution deals with. Masking is a technique that replaces or obscures sensitive data

  with dummy or random data, such as asterisks or hashes. Masking can help protect the privacy and security of the data, while still allowing for some analysis and reporting. Therefore, the correct answer is

  D.

  References:

  [Data Masking | Definition, Techniques and Examples - Talend], [Data masking - Wikipedia]

• Question 203:

  An analyst needs to join two tables of data together for analysis. All the names and cities in the first table should be joined with the corresponding ages in the second table, if applicable.

  

  Which of the following is the correct join the analyst should complete. and how many total rows will be in one table?

  A. INNER JOIN, two rows
  B. LEFT JOIN. four rows
  C. RIGHT JOIN. five rows
  D. OUTER JOIN, seven rows
  B. LEFT JOIN. four rows

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  Explanation

  The correct join the analyst should complete is

  B. LEFT JOIN, four rows. A LEFT JOIN is a type of SQL join that returns all the rows from the left table, and the matched rows from the right table. If there is no match, the right table will have null

  values. A LEFT JOIN is useful when we want to preserve the data from the left table, even if there is no corresponding data in the right table1 Using the example tables, a LEFT JOIN query would look like this:

  SELECT t1.Name, t1.City, t2.Age FROM Table1 t1 LEFT JOIN Table2 t2 ON t1.Name = t2.Name;

  The result of this query would be:

  Name City Age Jane Smith Detroit NULL John Smith Dallas 34 Candace Johnson Atlanta 45 Kyle Jacobs Chicago 39

  As you can see, the query returns four rows, one for each name in Table1. The name John Smith appears twice in Table2, but only one of them is matched with the name in Table1. The name Jane Smith does not appear in Table2, so the

  age column has a null value for that row.

• Question 204:

  What R package makes it easy to work with dates?

  A. Lubridate.
  B. Datemath.
  C. Stringr.
  D. ggplot.
  A. Lubridate.

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  Explanation

  Lubridate is an R package that makes it easier to work with dates and times.

• Question 205:

  Which of the following is the first step an analyst should perform upon receiving a business request for analysis?

  A. Determine the data needs and sources for analysis.
  B. Initiate the analysis for exploratory data analysis.
  C. Review the business questions to understand the scope.
  D. Finalize the methodology to solve the problem.
  C. Review the business questions to understand the scope.

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  Explanation

  Answer:

  C. Review the business questions to understand the scope. The first step an analyst should perform upon receiving a business request for analysis is to review the business questions to understand the scope of the problem, the

  objectives, and the expected outcomes. This will help the analyst to define the analytical approach, identify the data needs and sources, and plan the analysis process. Reviewing the business questions will also help the analyst to

  communicate with the stakeholders and clarify any assumptions or ambiguities.

  Option A is incorrect, as determining the data needs and sources for analysis is not the first step, but rather a subsequent step that depends on the business questions and the analytical approach. Option B is incorrect, as initiating the

  analysis for exploratory data analysis is not the first step, but rather a part of the analysis process that involves examining and summarizing the data, identifying patterns and outliers, and testing hypotheses.

  Option D is incorrect, as finalizing the methodology to solve the problem is not the first step, but rather a later step that involves selecting and applying the appropriate analytical techniques, tools, and models to answer the business questions.

• Question 206:

  An analyst is updating a customer contacts database with information obtained from a survey of new customers.

  Which of the following data manipulation techniques should the analyst use?

  A. Join
  B. Append
  C. Transform
  D. Blend
  B. Append

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  Explanation

• Question 207:

  Which of the following is concatenate typically used to combine?

  A. Rows
  B. Columns
  C. Tables
  D. Databases
  B. Columns

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  Explanation

• Question 208:

  Which of the following data types best describe 4Ac1? (Select two).

  A. Alphanumeric
  B. Symbolic
  C. Numeric
  D. Float
  E. Boolean
  F. String
  A. Alphanumeric
  F. String

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  Explanation

  The term `4Ac1' is a combination of numbers and letters, which fits the definition of an alphanumeric string. Alphanumeric refers to a character set that contains both letters and numbers. In data analytics and programming, such a value is

  typically treated as a string, which is a sequence of characters. Strings can include letters, digits, and various other symbols. A numeric data type would only include numbers, and a float is a specific kind of numeric data type that includes

  decimal points, neither of which applies to `4Ac1'. A boolean data type represents one of two values: true or false. Since `4Ac1' does not represent a true or false value, it cannot be classified as boolean. Lastly, symbolic is not a standard data

  type in the context of programming and data analytics.

  References:

  Understanding Python 3 data types.

  Basic Data Types in Python.

  Java Data Types.

• Question 209:

  Which of the ing is the correct ion for a tab-delimited spre file?

  A. tap
  B. tar
  C. sv
  D. az
  C. sv

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  Explanation

  A tab-delimited spreadsheet file is a type of flat text file that uses tabs as delimiters to separate data values in a table. The file extension for a tab-delimited spreadsheet file is usually .tsv, which stands for tab-separated values. Therefore, the

  correct answer is

  C.

  References:

  [Tab-separated values - Wikipedia], [What is a TSV File? | How to Open, Edit and Convert TSV Files]

• Question 210:

  Which of the following statistical methods requires two or more categorical variables?

  A. Simple linear regression
  B. Chi-squared test
  C. Z-test
  D. Two-sample t-test
  B. Chi-squared test

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  Explanation

  This is because a chi-squared test is a type of statistical method that tests the association or independence between two or more categorical variables, such as gender, race, or occupation. A chi-squared test can be used to compare the observed frequencies of the categories with the expected frequencies under the null hypothesis of no association or independence. For example, a chi-squared test can be used to determine if there is a relationship between smoking and lung cancer. The other statistical methods do not require two or more categorical variables. Here is why:

  Simple linear regression is a type of statistical method that models the relationship between a continuous dependent variable and a continuous or categorical independent variable, such as height, weight, or education level. A simple linear regression can be used to estimate the slope and intercept of the best-fitting line that describes how the dependent variable changes with the independent variable. For example, a simple linear regression can be used to predict the weight of a person based on their height. Z-test is a type of statistical method that tests the significance of the difference between a sample mean and a population mean, or between two sample means, when the population standard deviation or the sample sizes are large enough. A z-test can be used to compare the average scores of two groups of students on a standardized test. Two-sample t-test is a type of statistical method that tests the significance of the difference between two sample means when the population standard deviation is unknown or the sample sizes are small. A two-sample t-test can be used to compare the average salaries of two groups of employees in different departments.