ISAT - International Student Admissions Test International Student Admissions Interpreting Scientific Data 1

Question 1

A study comparing two pain medications reports: Drug A reduced pain scores by 18 points (95% CI: 14–22), Drug B reduced pain scores by 15 points (95% CI: 11–19).
What can researchers most accurately conclude?

Accepted Answer

The results are inconclusive because the confidence intervals overlap

Answer

Drug A is significantly better than Drug B because it has a higher mean reduction

Answer

The two drugs cannot be compared because confidence intervals were used

Answer

Drug B should be discarded since it has a lower mean reduction

Question 2

Researchers test whether sleep duration affects exam scores. They find r = –0.61 between hours of sleep deprivation and exam performance. Which conclusion is best supported?

Accepted Answer

There is a strong negative association between sleep deprivation and exam scores

Answer

Sleeping more causes students to perform better on exams

Answer

Sleep deprivation explains 61% of the variation in exam scores

Answer

Students who sleep less will always score lower on exams

Question 3

A scatter plot shows the relationship between study hours and test scores for 40 students. The line of best fit has a positive slope, but several data points are widely scattered around the line. What does this pattern suggest?

Accepted Answer

Study hours is a positive but imperfect predictor of test scores

Answer

Study hours is a perfect predictor of test scores

Answer

There is no relationship between study hours and test scores

Answer

The data contains an error and should be discarded

Question 4

In a longitudinal study, Group A (n=100) receives a dietary intervention and Group B (n=100) receives no intervention. After 6 months, Group A shows a 5% reduction in cholesterol and Group B shows a 4.8% reduction. The p-value is 0.74. What should the researchers conclude?

Accepted Answer

There is insufficient evidence that the intervention caused a significant difference

Answer

The dietary intervention is effective because Group A had a larger reduction

Answer

The study is invalid because both groups showed cholesterol reduction

Answer

A larger study would definitely prove the intervention is effective

Question 5

A table shows bacterial colony counts at three temperatures: 25°C = 340 colonies (SD=45), 35°C = 890 colonies (SD=52), 45°C = 210 colonies (SD=48), with n=20 samples each. Which conclusion is best supported by the data?

Accepted Answer

Bacteria grow best at 35°C, and this difference is likely meaningful given the large gap and small SDs

Answer

Temperature has no effect on bacterial growth because all SDs overlap

Answer

The experiment is flawed because three conditions were tested simultaneously

Answer

Bacterial growth at 25°C and 45°C are statistically identical

Question 6

A clinical study reports that patients taking Drug X have a 2% absolute risk reduction in heart attacks compared to a placebo. The relative risk reduction is reported as 40%. A journalist headlines: 'Drug X cuts heart attack risk by 40%.' What is the most accurate critique of this headline?

Accepted Answer

The headline is misleading because it uses relative risk reduction without providing the absolute baseline risk

Answer

The headline is accurate because 40% risk reduction is statistically significant

Answer

The headline should instead report the p-value to be meaningful

Answer

Both the absolute and relative risk figures are equally informative for the general public