Data Science Statistical Concepts and Inference 5

Question 1

A researcher conducts 20 independent tests at alpha = 0.05 with all nulls true; roughly how many false positives are expected?

Accepted Answer

1

Answer

0

Answer

5

Answer

20

Question 2

The Bonferroni correction is used to:

Accepted Answer

Control the family-wise error rate across multiple comparisons

Answer

Increase statistical power

Answer

Estimate effect sizes

Answer

Normalize skewed data

Question 3

Bootstrapping is primarily used to:

Accepted Answer

Estimate the sampling distribution of a statistic by resampling with replacement

Answer

Increase the true sample size

Answer

Remove outliers automatically

Answer

Prove causation

Question 4

Which condition is a key assumption of ordinary linear regression?

Accepted Answer

Residuals have constant variance (homoscedasticity)

Answer

Predictors must be categorical

Answer

The outcome must be binary

Answer

Residuals must be perfectly correlated

Question 5

A Type II error occurs when a test:

Accepted Answer

Fails to reject a false null hypothesis

Answer

Rejects a true null hypothesis

Answer

Uses the wrong alpha level

Answer

Has too large a sample

Question 6

Selection bias most directly threatens which property of a study?

Accepted Answer

The internal validity and representativeness of the sample

Answer

The arithmetic of the mean

Answer

The number of decimal places reported

Answer

The choice of font in the report

Question 7

What does a wide confidence interval typically indicate about an estimate?

Accepted Answer

Greater uncertainty about the parameter

Answer

High precision

Answer

A guaranteed correct result

Answer

A small standard error