DAC Statistical Methods & Analytics Flashcards
6 cards from real DAC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 DAC Statistical Methods & Analytics flashcards as text
What is the difference between a population and a sample in statistics?
Answer: A population includes all members of a group; a sample is a subset selected for study
A population is the complete set of all individuals or items of interest, while a sample is a smaller subset drawn from the population for analysis.
Which statistical test is appropriate for comparing the means of two independent groups?
Answer: Independent samples t-test
The independent samples t-test compares the means of two unrelated groups to determine if there is a statistically significant difference.
What does a positively skewed distribution indicate about the data?
Answer: Most values are concentrated on the left side with a long right tail
In a positively skewed distribution, the tail extends to the right, meaning most data values are lower but a few extreme high values pull the mean upward.
In regression analysis, what does the R-squared value represent?
Answer: The proportion of variance in the dependent variable explained by the independent variables
R-squared (coefficient of determination) measures the proportion of variance in the outcome variable that is explained by the predictor variables in the model.
What is the purpose of ANOVA (Analysis of Variance)?
Answer: To compare the means of three or more groups simultaneously
ANOVA tests whether the means of three or more independent groups are statistically different from each other, using variance within and between groups.
Which probability distribution is symmetric and bell-shaped, often used as a basis for statistical inference?
Answer: Normal distribution
The normal distribution is a symmetric, bell-shaped continuous probability distribution fundamental to many statistical methods and the Central Limit Theorem.