ISAT Interpreting Scientific Data 3

Question 1

A data table shows average rainfall (mm) and crop yield (tons/hectare) for 8 regions. As rainfall increases, crop yield increases up to 800 mm, then decreases. What type of relationship is this?

Accepted Answer

Non-linear (curvilinear) relationship

Answer

A relationship that increases then decreases forms a curve (inverted U-shape), which is a non-linear or curvilinear pattern.

Question 2

A scientist graphs reaction rate (y-axis) versus enzyme concentration (x-axis). The graph levels off at a maximum rate. What most likely explains the plateau?

Accepted Answer

The substrate concentration has become the limiting factor

Answer

When enzyme concentration exceeds available substrate, reaction rate plateaus because substrate is now the limiting factor.

Question 3

Two overlapping histograms compare the distribution of exam scores for morning vs. afternoon test-takers. Both distributions are roughly symmetric. The morning peak is at 75 and the afternoon peak is at 68. What can be concluded?

Accepted Answer

Morning test-takers scored higher on average in this dataset

Answer

The data shows a difference in central tendency (peak scores), but cannot establish causation or compare exam difficulty without additional information.

Question 4

A researcher finds a strong negative correlation (r = −0.89) between hours of sleep and number of errors on a cognitive task. What does this correlation value indicate?

Accepted Answer

As sleep hours increase, errors tend to decrease strongly

Answer

r = −0.89 indicates a strong negative correlation: as one variable increases, the other tends to decrease, though correlation does not imply causation.

Question 5

A toxicology study reports the LD50 of a substance as 200 mg/kg. What does this value represent?

Accepted Answer

The dose lethal to 50% of a test population

Answer

LD50 (lethal dose 50) is the dose required to kill half of a tested population, used as a standard measure of acute toxicity.

ISAT - International Student Admissions Test Practice Test

ISAT - International Student Admissions Test Practice Test

ISAT Interpreting Scientific Data 3