Practice Test GeeksDSE - Data Science Practice Test
← All DSE Flashcard Decks

Statistical Inference and Hypothesis Testing Flashcards

7 cards from real DSE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Statistical Inference and Hypothesis Testing flashcards as text

  1. A researcher sets α = 0.01 instead of α = 0.05. What is the direct consequence?

    Answer: Reduced probability of a Type I error

    Lowering α makes the rejection region smaller, directly reducing the probability of falsely rejecting a true null hypothesis (Type I error).

  2. Which condition must hold for the Central Limit Theorem to justify using a z-test on non-normal data?

    Answer: Sample size must be sufficiently large (typically n ≥ 30)

    The CLT states that sample means approach normality as n grows, making large samples the key requirement for z-tests on non-normal populations.

  3. A 95% confidence interval for a mean is (12.3, 17.7). What is the correct interpretation?

    Answer: If we repeated this procedure many times, 95% of such intervals would contain the true mean

    Confidence intervals are a long-run frequency statement about the procedure, not a probability statement about a fixed (unknown) parameter.

  4. The Bonferroni correction addresses which problem in multiple hypothesis testing?

    Answer: Inflated familywise Type I error rate

    Running many tests at α = 0.05 each inflates the chance of at least one false positive; Bonferroni divides α by the number of tests to control the familywise error rate.

  5. A paired t-test is preferred over an independent samples t-test when:

    Answer: Each observation in one group is naturally matched to one in the other

    Pairing (e.g., before/after measurements on the same subject) removes between-subject variability, increasing power via the paired design.

  6. Under the null hypothesis, a p-value of 0.03 means:

    Answer: The observed result or one more extreme would occur 3% of the time by chance alone

    A p-value is the probability of observing data at least as extreme as the sample data, assuming H₀ is true.

  7. Which test statistic is appropriate for comparing the variances of two independent normal populations?

    Answer: F-statistic

    The F-test uses the ratio of two sample variances, which follows an F-distribution under the null hypothesis of equal population variances.