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 Analysis flashcards as text
In hypothesis testing, what does a p-value of 0.03 mean at the 0.05 significance level?
Answer: Reject the null hypothesis
A p-value below the significance threshold of 0.05 leads to rejecting the null hypothesis.
What does a 95% confidence interval for a mean represent?
Answer: A range that would contain the true mean in 95% of repeated samples
The confidence level reflects how often the interval would capture the true parameter over repeated sampling.
A Type I error in hypothesis testing is:
Answer: Rejecting a true null hypothesis (false positive)
A Type I error wrongly rejects a null that is actually true, a false positive.
Increasing the sample size generally has what effect on the standard error of the mean?
Answer: It decreases
Standard error shrinks proportionally to 1 over the square root of the sample size.
Which test compares the means of two independent groups?
Answer: Independent samples t-test
The independent samples t-test evaluates whether two group means differ significantly.
The Central Limit Theorem states that the sampling distribution of the mean:
Answer: Approaches normal as sample size grows, regardless of population shape
For large samples, the distribution of sample means tends toward normality even if the population is not normal.
A chi-square test of independence is used to assess:
Answer: Association between two categorical variables
The chi-square test checks whether two categorical variables are related using observed versus expected counts.