Given the following customer and order tables:
Which of the following describes the number of rows and columns of data that would be present after performing an INNER JOIN of the tables?
Correct Answer:B
This is because an INNER JOIN is a type of join that combines two tables based on a matching condition and returns only the rows that satisfy the condition. An
INNER JOIN can be used to merge data from different tables that have a common column or a key, such as customer ID or order ID. To perform an INNER JOIN of the customer and order tables, we can use the following SQL statement:
This statement will select all the columns (*) from both tables and join them on the customer ID column, which is the common column between them. The result of this statement will be a new table that has seven rows and eight columns, as shown below:
The reason why there are seven rows and eight columns in the result table is because:
✑ There are seven rows because there are six customers and six orders in the original tables, but only five customers have matching orders based on the customer ID column. Therefore, only five rows will have data from both tables, while one row will have data only from the customer table (customer 5), and one row will have no data at all (null values).
✑ There are eight columns because there are four columns in each of the original tables, and all of them are selected and joined in the result table. Therefore, the result table will have four columns from the customer table (customer ID, first name, last name, and email) and four columns from the order table (order ID, order date, product, and quantity).
An analyst has generated a report that includes the number of months in the first two quarters of 2019 when sales exceeded $50,000:
Which of the following functions did the analyst use to generate the data in the Sales_indicator column?
Correct Answer:B
This is because a logical function is a type of function that returns a value based on a condition or a set of conditions. A logical function can be used to generate the data in the Sales_indicator column by comparing the values in the Sales column with a threshold of $50,000 and returning either ??Exceeded $50,000?? or ??Not exceeded $50,000?? accordingly. For example, a logical function in Excel that can achieve this is:
The other functions are not suitable for generating the data in the Sales_indicator column. Here is why:
Aggregate is a type of function that performs a calculation on a group of values, such as sum, average, count, etc. An aggregate function cannot generate the data in the Sales_indicator column because it does not compare the values in the Sales column with a threshold or return a text value based on a condition.
Date is a type of function that manipulates or extracts information from dates, such as year, month, day, etc. A date function cannot generate the data in the Sales_indicator column because it does not use the values in the Sales column or return a text value based on a condition.
Sort is a type of function that arranges the values in a column or a range in ascending or descending order. A sort function cannot generate the data in the Sales_indicator column because it does not create a new column or return a text value based on a condition.
Five dogs have the following heights in millimeters: 300, 430, 170, 470, 600
Which of the following is the mean height for the five dogs?
Correct Answer:A
The mean height for the five dogs is calculated by adding up all the heights and dividing by the number of dogs. The formula is:
mean = (300 + 430 + 170 + 470 + 600) / 5 mean = 1970 / 5 mean = 394
Therefore, option A is correct.
Option B is incorrect because it is the median height, which is the middle value when the heights are arranged in ascending order.
Option C is incorrect because it is the mean height multiplied by 1.25.
Option D is incorrect because it is the mean height multiplied by 1.28.
Which of the following is a characteristic of a relational database?
Correct Answer:C
It is structured in nature. This is because a relational database is a type of database that organizes data into tables, which consist of rows and columns. A relational database is structured in nature, which means that the data has a predefined schema or format, and follows certain rules and constraints, such as primary keys, foreign keys, or referential integrity. A relational database can be used to store, query, and manipulate data using a structured query language (SQL). The other characteristics are not true for a relational database. Here is why:
It utilizes key-value pairs. This is not true for a relational database, because key-value pairs are a way of storing data that associates each value with a unique key, such as an identifier or a name. Key-value pairs are typically used in non-relational databases, such as NoSQL databases, which do not have tables, rows, or columns, but rather store data in various formats, such as documents, graphs, or columns.
It has undefined fields. This is not true for a relational database, because fields are another name for columns in a table, which define the attributes or properties of each row or record in the table. Fields have defined names, types, and lengths in a relational database, which specify the format and size of the data that can be stored in each field.
It uses minimal memory. This is not true for a relational database, because memory is the amount of space or storage that is used by a database to store and process data. Memory usage depends on various factors, such as the size, complexity, and number of tables and queries in a relational database. A relational database can use a lot of memory if it has many tables with many rows and columns, or if it performs complex or frequent queries on the data.
Given the following graph:
Which of the following summary statements upholds integrity in data reporting?
Correct Answer:B
Strategy 4 provides the best sales in comparison to other strategies. This is because the total sales for Strategy 4 are the highest among all the strategies, as shown by the black line. The other statements are not accurate or do not uphold integrity in data reporting. Here is why:
Statement A is false because sales are not approximately equal for Product A and Product B across all strategies. For example, in Strategy 1, Product A has more sales than Product B, while in Strategy 3, Product B has more sales than Product A.
Statement C is misleading because it does not account for the difference in scale between the products. While Strategy 2 has the highest total sales among all products, it does not necessarily mean that it is the most effective for each product. For instance, Product D has very low sales in Strategy 2 compared to other strategies.
Statement D is biased because it does not provide any evidence or justification for why Product D should be promoted more than the other products in all strategies. It also ignores the fact that Product D has the lowest sales among all products in most of the strategies.