Question

explain the pros and cons of grouping data into classes vs. using the raw data.

Answer 1

Grouping data into classes:

Advantages:

1. It focuses on important subpopulations and ignores irrelevant ones.

2. Improves the accuracy/efficiency of estimation.

3. Permits greater balancing of statistical power of tests of differences between strata by sampling equal numbers from strata varying widely in size.

Disadvantages:

1. Requires selection of relevant stratification variables which can be difficult.

2. It is not useful when there are no homogeneous subgroups.

3. It can be expensive to implement.