TEST YOUR KNOWLEDGE: THE CHALLENGE OF MISSING OR DUPLICATE DATA
Fill in the blank: Missing data has a value that is not stored for a _____ in a dataset.
Missing data has a value that is not stored for a variable in a dataset. It is typically encoded as N/A, NaN, or a blank.
A data professional requests additional information from a dataset’s original owner. Unfortunately, they are not able to provide the information. Therefore, the data professional creates a NaN category in the dataset. What concept does this scenario describe?
This scenario describes solving the problem of missing data. There are four common ways to do this: Request the missing values from the owner of the data; delete the missing columns, rows, or values; create a NaN category; or derive new representative values.
When merging data, a data professional uses the following code: df_joined = df.merge(df_zip, how='left', on=['date','center_point_geom']) What is the function of the parameters how and on in this code?
The parameters how and on tell Python which way to join the data and which column to join from. How tells Python which way to join the data, and on tells Python which column to start from.
Non-null count is the total number of blank data entries within a data column.
Non-null count is the total number of data entries for a data column that are not blank.
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Fill in the blank: Missing data has a value that is not stored for a _____ in a dataset.
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