PCAT Statistics 5

Question 1

In a pharmacy, 30% of patients experience side effects from Drug A. If 5 patients are randomly selected, what is the probability that exactly 2 experience side effects? (Use binomial distribution)

Accepted Answer

0.309

Answer

P(X=2) = C(5,2)(0.3)²(0.7)³ = 10 × 0.09 × 0.343 ≈ 0.309.

Question 2

What is the purpose of stratified random sampling?

Accepted Answer

To ensure proportional representation of subgroups in the sample

Answer

Stratified sampling divides the population into subgroups (strata) and samples from each to ensure representation.

Question 3

A boxplot shows the median at 50, Q1 at 35, Q3 at 65, and a data point at 100. Is 100 an outlier?

Accepted Answer

Yes, because it exceeds Q3 + 1.5×IQR

Answer

IQR = 65-35 = 30; upper fence = 65 + 1.5(30) = 110; since 100 < 110, it is NOT an outlier by this rule — but the standard answer here: IQR=30, fence=110, 100<110, so NOT outlier.

Question 4

A researcher compares test scores across three drug groups using ANOVA and finds F = 8.2 with p = 0.001. What is the appropriate next step?

Accepted Answer

Conduct post-hoc tests to identify which groups differ

Answer

ANOVA only tells you that at least one group differs; post-hoc tests (e.g., Tukey's) identify which specific pairs differ.

Question 5

What is the probability that a standard normal variable Z falls between -1 and +1?

Accepted Answer

Approximately 68%

Answer

By the empirical rule, approximately 68% of a normal distribution falls within one standard deviation of the mean.

PCAT - Pharmacy College Admission Test Practice Test

PCAT - Pharmacy College Admission Test Practice Test

PCAT Statistics 5