Imputing values is valid only if the variable values are We may replace missing values with the ...

Ans. #1

c
RATIONALE: Options for replacing the missing entries for a variable include replacing the missing value with the variable's mode, mean, or median. Imputing values in this manner is truly valid only if variable values are MCAR; otherwise, we may be introducing misleading information into the data.

Ans. #2

a
RATIONALE: An observation, or record, is the set of recorded values of variables associated with a single entity. It is displayed as a row of values in a spreadsheet or database in which the columns correspond to the variables.

Ans. #3

a
RATIONALE: If a model's implications depend on the inclusion or exclusion of outliers, then one should spend additional time to track down the cause of the outliers.

Ans. #4

a
RATIONALE: An observation, or record, is the set of recorded values of variables associated with a single entity. It is displayed as a row of values in a spreadsheet or database in which the columns correspond to the variables.

Makes more sense now, TY