Why are there blank entries for emission data mean in the LDS?

Why are there blank entries for emission data mean in the LDS?

• A. Data were intentionally omitted.
• B. Emission data was not available for all cars.
• C. Data were only for new models.
• D. Data were not collected in the same year.

Answer: (B)

The main idea here is understanding what a blank in a data set means. Blank entries for the emission data mean that the information wasn’t available for all cars in the sample. When some cars don’t have measured emission values, there isn’t enough data to calculate a mean for that group, so the entry is left blank. This reflects missing data rather than a value like zero or a deliberate omission. Other possibilities would imply a different pattern (for example, blanks only for newer models or only for a certain year), but the simplest and most accurate explanation in this context is that emission data wasn’t available for all cars.

The main idea here is understanding what a blank in a data set means. Blank entries for the emission data mean that the information wasn’t available for all cars in the sample. When some cars don’t have measured emission values, there isn’t enough data to calculate a mean for that group, so the entry is left blank. This reflects missing data rather than a value like zero or a deliberate omission.

Other possibilities would imply a different pattern (for example, blanks only for newer models or only for a certain year), but the simplest and most accurate explanation in this context is that emission data wasn’t available for all cars.