NCDAP Data Analysis & Statistics 3

Question 1

A survey of 200 students found that 80 students prefer online classes. What fraction of students prefer online classes?

Accepted Answer

2/5

Answer

80/200 simplifies to 2/5, so two-fifths of students prefer online classes.

Question 2

A scatterplot shows a positive correlation between hours studied and test scores. This means:

Accepted Answer

As hours studied increase, test scores tend to increase

Answer

A positive correlation means both variables move in the same direction — more study hours correspond to higher scores.

Question 3

The heights of five plants (in cm) are: 12, 15, 18, 15, 20. What is the mean height?

Accepted Answer

16

Answer

Sum = 12+15+18+15+20 = 80; mean = 80 ÷ 5 = 16 cm.

Question 4

Which graph type is BEST for showing how a quantity changes over time?

Accepted Answer

Line graph

Answer

A line graph is specifically designed to display trends and changes over a continuous time interval.

Question 5

Two events are independent if:

Accepted Answer

The outcome of one does not affect the outcome of the other

Answer

Independent events have no influence on each other; the probability of one occurring does not change based on the other.

(NCDAP) North Carolina Diagnostic Placement Test Practice Test