Excel
What is the difference between a VLOOKUP and Index Match?
VLOOKUP value must be in the first column of the table While INDEX returns a value from a range and MATCH returns the position of a value in a range.
What is the difference between DATE_PART and DATE_TRUNC data in SQL?
DATE_TRUNC is continuous and DATE_PART is Discrete.
or
DATEPART returns an INTEGER value; DATETRUNC returns a DATE
What is Chloropleth Chart used for?
Used to represent spatial data
What is the difference between Mean, Median and Mode ?
Mean : is the average of all the values in the data set. It is calculated by adding all the values and dividing by the number of values.
Median : is the middle value when all the values are ranked from least to greatest. If there is an even number of values, the median is the average of the two middle values.
Mode : is the value that appears most often in the data set.
What is the difference between .append() and .extend()?
.append() : Inserts as a value at the end of the list
.extend() : Combines a list with another list
This command/tool allows you to remove information from sight (NOT DELETE IT) and only see the information you want
FILTER
What is the difference between WHERE and HAVING?
WHERE filters individual rows
HAVING filters groups (aggregates)
What is the use of Calculated fields in Tableau?
Calculated fields allow you to create new data from data that already exists in your data source. (Create a new column)
How to calculate IQR (Interquartile Range)?
Takes the third quartile value and subtracts the first quartile value.
IQR=Q3-Q1
What are the main TWO differences between List, Tuple, and Set?
List:[] , ordered, mutable, non-unique
Tuple: () , ordered, immutable, non-unique
Set: {} , unordered, mutable, unique
Audio, Video, or Images.
Where can you place a Subquery ?
In terms of the mean and median, how can we determine if a distribution is skewed and in what direction?
A distribution is left-skewed if the mean is less than the median.
A distribution is right-skewed if the mean is greater than the median
What does the coefficient of correlation indicate? What is the range of values?
Correlation coefficients are used to measure the strength of the linear relationship between two variables. A correlation coefficient greater than zero indicates a positive relationship while a value less than zero signifies a negative relationship. Range +1 to -1
What is the type of error in the following code:
num= 123.467.1
SyntaxError
What do we use when we want to highlight cells that meet a certain criteria?
Conditional formatting.
Name 3 basic conditions both tables need to meet in order for a INNER JOIN, LEFT JOIN, RIGHT JOIN to occur?
Both tables must have a common column.
The common column must be unique in each table.
The common column must contain the same data type in both tables.
Both common column data should match
What chart best represent Quartiles?
A box and whisker chart (boxplot) shows distribution of data into quartiles, highlighting the mean and outliers.
In standard deviation, what is the 68-95-99.7 Rule?
The standard deviation is a measure of how spread out a set of data and 68% of data are within one standard deviation, 95% within two standard deviations, and 99.7% within three standard deviations.
What does PANDAS stand for?
PANEL DATA
A column with 50 cells, of which 42 are numbers, 5 are text, and the rest are empty cells. What is the result of this formula?
=COUNT(A1:A50)+COUNTA(A1:A50)+COUNTBLANK(A1:A50)
92
What is the difference between a UNION and a JOIN?
JOIN : combines data by matching rows from the two tables based on a common column.
UNION : combines data by adding rows from the two tables together, even if the rows do not have any matching columns.
What is Data-Ink Ratio?
A principle states that extra info should not distract from key relations
What is the main difference between the Population and the Sample Standard Deviation Formula?
The population standard deviation formula uses the population size (N), while the sample standard deviation formula uses the sample size minus one (n-1).
What is the type of error in the following code:
d={ 1:'Python', '2':'Excel',3:'PowerBi',4:'Tableau'}
d[2]
KeyError