Collecting data is usually easier than collecting data because the assessment can usually be done more quickly by a simple inspection or count.
a. simple; complex
b. variable; attribute
c. conformances; nonconformances
d. attribute; variable

d. attribute; variable

It is easier to collect 'attribute' data than it is to collect 'variable' data.

Explanation:

Attribute data has to do with numbers. It has characteristics which can be counted and provides less information than variable data does.

Variable data deals more with measurements and usually goes further to give more information than what can be obtained from attribute data.

For example, whereas attribute data may classify 10 students into categories of 5 tall and 5 short students, variable data goes ahead to provide their height measurements.

It is therefore easier to collect attribute data than it is to collect variable data and this can be done by a simple inspection or count.