Statistical Analysis & Software Flashcards

A researcher uses ANCOVA instead of ANOVA. What is the primary advantage of this approach?

Answer: It controls for the influence of one or more covariates, reducing error variance

ANCOVA statistically controls for covariates (continuous confounding variables), which reduces unexplained error variance and increases sensitivity to detect treatment effects.

Which data visualization is most appropriate for showing the relationship between two continuous variables?

Answer: Scatterplot

A scatterplot displays individual data points on two continuous axes, allowing visual assessment of direction, strength, and form of the bivariate relationship.

In survey research, what does 'listwise deletion' refer to in handling missing data?

Answer: Excluding any case with missing data on any analysis variable

Listwise deletion (complete case analysis) removes entire cases from analysis if they have missing data on any variable included in the analysis.

What is the key distinction between parametric and non-parametric statistical tests?

Answer: Parametric tests make assumptions about population distribution parameters; non-parametric tests do not

Parametric tests assume the data come from populations with specific distributions (typically normal) and estimate population parameters, whereas non-parametric tests make no such distributional assumptions.

In SAS, what does PROC MEANS primarily compute?

Answer: Descriptive statistics such as mean, standard deviation, and n for numeric variables

PROC MEANS computes descriptive statistics including N, mean, standard deviation, minimum, and maximum for numeric variables in a SAS dataset.

When interpreting a 95% confidence interval for a mean, which statement is correct?

Answer: If the study were repeated many times, 95% of such intervals would contain the true population mean

A 95% CI is a frequentist concept meaning that in repeated sampling, 95% of constructed intervals would capture the true population parameter.

Which test is most appropriate when comparing the median scores of the same participants under three different conditions?

Answer: Friedman Test

The Friedman test is the non-parametric equivalent of the one-way repeated-measures ANOVA, used when the same subjects are measured under three or more conditions.