Inference &
Proportions
Proportions
This type of inference test is used to determine if there’s a statistically significant difference in interest in online fitness classes between two age groups.
What is a two-sample z-test for proportions?
This visual tool helps compare the distribution of bottle sizes sold at two schools and is useful for representing categorical data proportions across groups.
What is a segmented bar graph (or mosaic plot)?
This is the term for a study in which the researcher does not assign treatments but only observes outcomes.
What is an observational study?
This is the type of distribution that models the number of geodes opened until a red crystal is found.
What is a geometric distribution?
This test checks for an association between two categorical variables.
What is a chi-square test of independence?
The condition that must be met to use a normal approximation for the sampling distribution of sample proportions.
What is the success/failure condition (np ≥ 10 and n(1−p) ≥ 10)?
A type of graph appropriate for comparing data from two categorical variables.
What is a mosaic plot?
The benefit of random assignment in an experiment.
What is to reduce bias and create comparable groups?
The expected value (mean) of a geometric distribution with p = 0.08.
What is 1/p = 12.5?
This is the condition for using a chi-square test regarding expected counts.
What is all expected counts must be at least 5?
This is the interpretation of a 95% confidence interval for the difference in proportions.
What is: we are 95% confident that the interval captures the true difference in proportions?
The key features to describe when comparing distributions from a graph.
What are shape, center, spread, and outliers?
This type of experimental design allows subjects to experience both treatments.
What is a matched pairs design?
The standard deviation of a geometric distribution with p = 0.08.
What is √((1−p)/p²) ≈ 11.91?
The degrees of freedom for a two-way table with 2 rows and 5 columns.
What is (2−1)(5−1) = 4?
The name of the value used from a table that defines how many standard errors we extend for a confidence interval.
What is a critical value (z or t*)?
What to look for in a mosaic plot to determine a higher proportion.
What is a wider section representing the category of interest?
The change needed for a study’s results to be generalized to a population.
What is random sampling from the population?
The probability that the first success occurs on the third trial.
What is (1−p)² × p?
The interpretation of a small p-value in a chi-square test.
What is evidence of an association between the variables?
This is what it means if the p-value is less than the significance level alpha.
What is: we reject the null hypothesis and conclude there is evidence for the alternative?
The difference between comparing proportions and comparing counts in visual data.
What is proportions relate to relative comparisons while counts refer to raw totals?
The three key principles of experimental design.
What are control, randomization, and replication?
The mean of a custom random variable Y given a truncated geometric distribution.
What is E(Y) = Σ[y × P(Y=y)] for y = 1 to 4?
The null and alternative hypotheses for a test of independence.
What are H₀: The variables are independent; H₁: The variables are not independent?