Data Science Statistical Concepts and Analysis 3

Question 1

Which sampling method gives every member of a population an equal chance of selection?

Accepted Answer

Simple random sampling

Answer

Simple random sampling ensures each unit has an identical probability of being chosen.

Question 2

The standard deviation measures:

Accepted Answer

The typical spread of values around the mean

Answer

Standard deviation quantifies average dispersion of data points from the mean.

Question 3

In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?

Accepted Answer

68%

Answer

The empirical rule states about 68% of values lie within ±1 standard deviation.

Question 4

Which is an example of a categorical (nominal) variable?

Accepted Answer

Eye color

Answer

Eye color labels categories with no inherent numeric order, making it nominal.

Question 5

If two events are mutually exclusive, then:

Accepted Answer

They cannot occur at the same time

Answer

Mutually exclusive events have no overlap, so they cannot both happen simultaneously.

Data Science Practice Test