Observations that deal with descriptions that cannot be expressed in numbers are called
a.

manipulated observations.

c.

qualitative observations.

b.

quantitative observations.

d.

operational observations.

Option (c) is the correct answer.

Explanation:

An observation that can only be expressed through words and not with numbers is known as qualitative observation.

For example, color of a substance cannot be expressed in numbers. Hence, it is a qualitative observation.

On the other hand, an observation that can be expressed in number is known as a quantitative observation.

For example, height of a person can be expressed through numbers. Hence, it is a quantitative observation.

Thus, we can conclude that observations that deal with descriptions that cannot be expressed in numbers are called qualitative observations.