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

With a 5% error rate per test, about 1 in 20 tests is expected to be a false positive.

Question 2

The Bonferroni correction is used to:

Accepted Answer

Control the family-wise error rate across multiple comparisons

Answer

Bonferroni adjusts the significance threshold to limit the chance of any false positive across many tests.

Question 3

Bootstrapping is primarily used to:

Accepted Answer

Estimate the sampling distribution of a statistic by resampling with replacement

Answer

Bootstrapping resamples the observed data with replacement to approximate the sampling distribution of a statistic.

Question 4

Which condition is a key assumption of ordinary linear regression?

Accepted Answer

Residuals have constant variance (homoscedasticity)

Answer

Linear regression assumes residuals have roughly constant variance across fitted values.

Question 5

A Type II error occurs when a test:

Accepted Answer

Fails to reject a false null hypothesis

Answer

A Type II error is a false negative: failing to detect a true effect.

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