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Statistical Concepts and Analysis Flashcards

7 cards from real Data Science 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 Concepts and Analysis flashcards as text

  1. A dataset of household incomes has a few extreme high values. Which measure of central tendency is LEAST affected by these outliers?

    Answer: Median

    The median is based on rank position, so extreme values do not pull it like they pull the mean.

  2. A p-value of 0.03 in a test with significance level 0.05 means:

    Answer: Reject the null hypothesis

    When the p-value is below alpha, the result is statistically significant and the null hypothesis is rejected.

  3. Which statement best describes the Central Limit Theorem?

    Answer: The sampling distribution of the mean approaches normality as sample size grows

    The CLT states the distribution of sample means tends toward normal regardless of the population shape as n increases.

  4. A correlation coefficient of -0.85 between two variables indicates:

    Answer: A strong negative linear relationship

    Values near -1 indicate a strong inverse linear association.

  5. What does a 95% confidence interval for a mean actually represent?

    Answer: A range that would contain the true mean in 95% of repeated samples

    The confidence level refers to the long-run proportion of such intervals capturing the true parameter.

  6. Which type of error occurs when you reject a null hypothesis that is actually true?

    Answer: Type I error

    A Type I error is a false positive—rejecting a true null hypothesis.

  7. A distribution with a long tail extending to the right is described as:

    Answer: Right-skewed (positively skewed)

    A tail pointing toward higher values indicates positive (right) skew, with mean greater than median.