What is the main goal of data analysis in user studies?
Method for evaluating together facts and figures for solving a research problem
What is the data acquisition process?
Identify concepts to measure, plan how to measure them (surveys, logs, questionnaires, interviews, observation), ask several questions per concept, and use measurement scales.
What are the main scales of measurement?
Nominal (categories, no order), Ordinal (categories with order), Numerical (quantitative values).
Give examples of usability metrics in user studies.
Time to accomplish a task, number of errors, System Usability Scale (SUS) scores, pages visited.
What is the System Usability Scale (SUS)?
A standardized questionnaire with 10 items rated from 1 (strongly disagree) to 5 (strongly agree) to assess system usability.
What is data cleaning?
Removing duplicates, errors, missing values, detecting outliers, and normalizing data to ensure reliable analysis.
What are the two main types of statistical data analysis?
Descriptive (summarizes data, e.g., mean, standard deviation) and inferential (draws conclusions beyond the data, e.g., correlation, regression, t-tests, ANOVA).
What is regression analysis?
Predicts the value of a dependent variable based on the value of an independent variable.
What is the Pearson correlation coefficient?
A measure of linear correlation between two variables, ranging from -1 (perfect negative) to +1 (perfect positive), with 0 meaning no linear relationship.
What is the Spearman rank correlation coefficient?
A non-parametric measure of rank correlation, assessing how well the relationship between two variables can be described by a monotonic function.
What is statistical hypothesis testing?
A process to decide if observed findings are likely due to chance, involving stating null and alternative hypotheses, setting significance level (α), collecting data, calculating test statistics, and drawing conclusions.
What is a t-test?
A statistical test for comparing means, used for small samples when population standard deviation is unknown; includes one-sample, two-sample (paired/unpaired) tests.
What is ANOVA (Analysis of Variance)?
A statistical test for comparing means across more than two groups, using the F-distribution to assess significance.
What is the Chi-square test?
A non-parametric test for categorical data, comparing observed frequencies to expected ones to test independence between variables.
What is the Wilcoxon signed-rank test?
A non-parametric alternative to the paired t-test, used when data is not normally distributed, comparing the ranks of differences between paired samples.
What is the Mann-Whitney U test?
A non-parametric test for comparing two independent groups, based on the ranks of the data rather than their actual values.
Why is data cleaning important before analysis?
Because errors, outliers, and missing values can distort results and lead to incorrect conclusions.
What is statistical significance?
When the probability that observed findings are due to chance is very low, typically less than the chosen α level (e.g., 0.05).
What is the role of critical values in hypothesis testing?
Critical values define the threshold for rejecting the null hypothesis based on the chosen significance level and degrees of freedom.
What is the importance of reporting conclusions in user studies?
To interpret results in context, discuss methodology, significance, recommendations, and limitations of the analysis.
