Which one of the following is a measure of dispersion?
Correct Answer:A
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?
Correct Answer:D
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.
Which of the following is a difference between a primary key and a unique key?
Correct Answer:B
The correct answer is B. There can be only one primary key in a data set, whereas there can be multiple unique keys.
A primary key is a column or a set of columns that uniquely identifies each row in a table. A table can have only one primary key, which also enforces the NOT NULL constraint on the column(s) involved. A primary key can also be referenced by a foreign key of another table to establish a relationship between the tables12
A unique key is a column or a set of columns that also uniquely identifies each row in a table, but it is not the primary key. A table can have more than one unique key, which also allows one NULL value for the column(s) involved. A unique key can also be referenced by a foreign key of another table to establish a relationship between the tables12
Some of the differences between a primary key and a unique key are:
✑ A primary key creates a clustered index on the column(s), whereas a unique key creates a non-clustered index on the column(s)3
✑ A primary key does not allow any NULL values, whereas a unique key allows one
NULL value for the column(s)123
✑ A primary key can be a unique key, but a unique key cannot be a primary key12
A company wants to know how its customers interact with an e-commerce website based on clicks over items. Which of the following is the primary requirement for this report?
Correct Answer:B
Which of the following is the best approach to use to gain a general understanding of a data set?
Correct Answer:A