ETS Statistical Analysis 3

Question 1

A sample of 25 students has a mean test score of 80 and a standard deviation of 10. What is the standard error of the mean?

Accepted Answer

2

Answer

10

Answer

4

Answer

0.4

Question 2

In simple linear regression, the slope coefficient β₁ represents:

Accepted Answer

The expected change in y for a one-unit increase in x

Answer

The y-intercept when x = 0

Answer

The predicted value of y when x = 1

Answer

The correlation between x and y

Question 3

An ANOVA test is used primarily to compare:

Accepted Answer

Three or more population means

Answer

Two sample proportions

Answer

The variance of one sample to a known value

Answer

Two population variances

Question 4

If P(A) = 0.4 and P(B) = 0.3, and A and B are independent events, what is P(A ∩ B)?

Accepted Answer

0.12

Answer

0.70

Answer

0.10

Answer

0.58

Question 5

A positively skewed distribution has its tail extending to the right. Which relationship between mean, median, and mode is typically true?

Accepted Answer

Mode < Median < Mean

Answer

Mean < Median < Mode

Answer

Mean = Median = Mode

Answer

Median < Mode < Mean

Question 6

Which sampling method ensures every possible sample of size n has an equal chance of being selected?

Accepted Answer

Simple random sampling

Answer

Stratified random sampling

Answer

Cluster sampling

Answer

Systematic sampling

Question 7

The p-value in a hypothesis test represents:

Accepted Answer

The probability of obtaining results as extreme as observed, assuming H₀ is true

Answer

The probability that the null hypothesis is true

Answer

The probability of a Type II error

Answer

The confidence level of the test