An employer needs to maintain adequate office staffing during the winter and wants to track storm data. Which of the following data collection methods should the employer use?
Correct Answer:
B
For an employer looking to maintain adequate office staffing during winter while tracking storm data, the most effective method would be to use public databases. These databases often contain comprehensive records of weather patterns and storm data collected and verified by reputable meteorological organizations. Utilizing public databases allows for access to historical and real-time data that is crucial for making informed decisions about staffing during adverse weather conditions.
Web scraping (A) is not the most reliable method, as it may involve extracting data from various websites that might not always provide verified or consistent information. Observations © can be subjective and may not cover a wide enough area to be effective for decision-making on a larger scale. Weather surveys (D) could provide insights, but they are not as immediate or comprehensive as the data available in public databases. References:
✑ The systematic review on Big Data Analytics in Weather Forecasting suggests that
big data techniques and technologies can manage and analyze the huge volume of weather data from different resources, which supports the use of public databases1.
✑ NOAA??s approach to detecting severe weather events using instruments and
receiving information from storm spotters indicates the importance of reliable, collected data, which is typically stored in public databases2.
✑ The National Weather Service??s use of observational data collected by various
instruments, which are then fed into forecast models, further emphasizes the value of established data collection methods over individual observations or surveys3.
Which of the following is the best description of the term "data governance"?
Correct Answer:
D
Data governance refers to the overarching management of data??s availability, usability, integrity, and security within an organization. It involves setting policies and standards that govern data usage, determining data ownership, implementing data security measures, and ensuring that data is accessible for business insights while maintaining its quality. The goal of data governance is to ensure that data is consistent, trustworthy, and not misused, supporting compliance with data privacy regulations and enabling effective data analytics to optimize operations and drive business decision-making.
References:
✑ Understanding Data Governance and Its Importance1.
✑ The Role of Data Governance in Data Management2.
✑ Defining Data Governance and Its Business Value3.
While reviewing survey data, a research analyst notices data is missing from all the responses to a single question. Which of the following methods would BEST address this issue?
Correct Answer:
A
This is because missing data is a type of data quality issue that occurs when data is absent or incomplete in a data set, which can affect the accuracy and reliability of the analysis or process. Missing data can be caused by various factors, such as human error, system error, or non-response. Missing data can be addressed by using various methods, such as replacing missing data, which means filling in or imputing the missing values with some reasonable estimates, such as mean, median, mode, or regression. The other methods are not used to address missing data. Here is why:
✑ Remove duplicate data is a type of method that eliminates or reduces duplicate data, which is a type of data quality issue that occurs when data is repeated or copied in a data set. Removing duplicate data does not address missing data, but rather affects the quantity and validity of the data.
✑ Replace redundant data is a type of method that eliminates or reduces redundant data, which is a type of data quality issue that occurs when data is unnecessary or irrelevant for the analysis or purpose. Replacing redundant data does not address missing data, but rather affects the efficiency and performance of the analysis or process.
✑ Remove invalid data is a type of method that eliminates or reduces invalid data, which is a type of data quality issue that occurs when data is incorrect or inaccurate in a data set. Removing invalid data does not address missing data, but rather affects the validity and reliability of the analysis or process.
A data analyst needs to perform a full outer join of a customer's orders using the tables below:
Which of the following is the mean of the order quantity?
Correct Answer:
D
The correct answer is D. OUTER JOIN, seven rows.
An OUTER JOIN is a type of SQL join that returns all the rows from both tables, regardless of whether there is a match or not. If there is no match, the missing side will have null values. An OUTER JOIN can be either a LEFT JOIN, a RIGHT JOIN, or a FULL JOIN, depending on which table??s rows are preserved1
Using the example tables, a FULL OUTER JOIN query would look like this:
SELECT Cust_id, Order_id, Order_qty FROM Sales_table FULL OUTER JOIN Order_table ON Sales_table.Order_id = Order_table.Order_id;
The result of this query would be:
Cust_id | Order_id | Order_qty --------??---------??--------- 1 | 1 | 100 2 | 2 | 50 3 | 3 | 25 4 | 4 |
75 NULL | 5 | 10 NULL | 6 | 20 NULL | 7 | 15
As you can see, the query returns seven rows, one for each order in either table. The orders that are not in the Sales_table have null values for the Cust_id column.
To find the mean of the order quantity, we need to sum up the order quantities and divide by the number of rows. In this case, the mean is (100 + 50 + 25 + 75 + 10 + 20 + 15) / 7 = 42.14. Rounding to one decimal place, we get 42.1 as the mean of the order quantity.
What SQL command is used to delete an entire table from a database?
Correct Answer:
A
