STAT Data Interpretation from Graphs 4

Question 1

A box-and-whisker plot for a dataset shows: minimum=10, Q1=25, median=40, Q3=55, maximum=80. What is the interquartile range (IQR)?

Accepted Answer

30

Answer

IQR = Q3 − Q1 = 55 − 25 = 30.

Question 2

A line graph compares the growth of two populations over 10 years. Population A grows from 1,000 to 2,000; Population B grows from 500 to 1,200. Which population grew more in absolute terms?

Accepted Answer

Population A

Answer

Population A added 1,000 people while Population B added 700 people, so A had greater absolute growth.

Question 3

A bar graph shows the number of medals won by five countries in an Olympic event. If the graph's y-axis starts at 5 instead of 0, what potential misinterpretation could occur?

Accepted Answer

Differences between countries appear larger than they are

Answer

A truncated y-axis starting above zero makes bars appear disproportionately different, exaggerating the visual gap between countries.

Question 4

A histogram shows the distribution of ages in a sample, with most data concentrated between 20–40 and a long tail extending to age 80. What type of distribution is this?

Accepted Answer

Right-skewed (positively skewed) distribution

Answer

A long tail extending toward higher values (right side) defines a right-skewed or positively skewed distribution.

Question 5

A dual-axis graph shows monthly sales volume (bars, left axis) and average sale price (line, right axis). In March, volume is highest but price is lowest. What can be inferred?

Accepted Answer

High volume and low price may offset each other's revenue effects

Answer

Revenue = price × volume; with the highest volume offset by the lowest price, the net effect on revenue is ambiguous without exact numbers.

STAT - Special Tertiary Admissions Test Practice Test

STAT - Special Tertiary Admissions Test Practice Test

STAT Data Interpretation from Graphs 4