ISAT - International Student Admissions Interpreting Scientific Data 2

Question 1

A clinical trial: treatment group (250) shows 15% recovery, control group (250) shows 12% recovery. P-value is 0.23. What should researchers conclude?

Accepted Answer

The difference is not statistically significant (p > 0.05), so the difference may be due to chance

Answer

P=0.23 means 23% probability of seeing this difference by chance. This exceeds the 0.05 threshold.

Question 2

Plant growth under three light conditions: Red=12.4cm (SD=2.1), Blue=15.8cm (SD=1.9), White=14.2cm (SD=2.3), n=30 each. Which comparison is most likely statistically significant?

Accepted Answer

Red vs Blue

Answer

Red vs Blue has the largest mean difference (3.4cm) with relatively low standard deviations.

Question 3

Ice cream sales and drowning deaths are strongly correlated (r=0.92). What is the most appropriate interpretation?

Accepted Answer

A confounding variable (temperature/season) drives both independently

Answer

Hot weather increases both ice cream consumption and swimming activity, driving both variables independently.

Question 4

A vaccine is 90% effective. In 10,000 people (5,000 vaccinated, 5,000 not), 50 unvaccinated get the disease. How many vaccinated people would get it?

Accepted Answer

5

Answer

90% effective means 10% of the unvaccinated rate. Unvaccinated rate: 50/5000=1%. Vaccinated rate: 0.1%. Expected cases: 5.

Question 5

Regression: y = 3.2x + 42 (x=study hours, y=score). A student studies 12 hours. What does the model predict, and what does the y-intercept mean?

Accepted Answer

80.4; the predicted baseline score with zero study hours

Answer

y = 3.2(12) + 42 = 80.4. The y-intercept (42) represents the predicted score when x=0.

ISAT - International Student Admissions Test Practice Test

ISAT - International Student Admissions Test Practice Test

ISAT - International Student Admissions Interpreting Scientific Data 2