Review session 1

Weeks 1-3 [L1, L2, L3]: study design, data semantics, and descriptive statistics

Outcomes

  • [L1] design a data collection scheme based on simple random sampling or simple experimental designs

  • [L2] distinguish between observational studies and experiments and understand the limitations (practical and consequential) of each

  • [L3] summarize data using graphical and numerical techniques

Lecture/lab recap

Week/day Lecture Lab
1/W Experiments and observational studies Reading abstracts
2/M Data vocabulary, proportions and means, common notation Loading data, extracting variables, computing means and proportions
2/W Measures of location/center and spread, simple graphics Histograms, barplots, summary statistics
3/M Graphics and tables for two variables, interpreting relationships, correlation Stacked bar plots, side-by-side boxplots, scatterplots

Assignment recap

Problem set Topics
PS1 Interpreting study descriptions
PS2 Summary statistics (mean, proportion) for one variable; identifying variable types
PS3 Measures of location and spread for one variable; visualizing frequency distributions
PS4 Visualizing relationships between two variables (C/C, C/N, N/N)

Questions: [L1, L2] study design

  • Experiment or observational study?
  • Describe the population
  • Describe the sample
  • Identify the outcomes
  • Identify variable types

Questions: [L3] descriptive statistics

  • Compute/interpret mean/median/percentiles/IQR/variance/SD
  • Compute/interpret a grouped summary with one or more of the above measures
  • Determine appropriate measures of location/center/spread
  • Make/interpret a table of proportions for values of a categorical variable
  • Make/interpret a contingency table
  • Make/interpret a histogram
  • Make/interpret two-way tables of proportions
  • Make/interpret stacked bar plots representing proportions
  • Make/interpret side-by-side boxplots
  • Make/interpret scatterplots
  • Compute/interpret correlations

Commonly missed question types

Identifying appropriate measures of center/spread (i.e., understanding robustness) Grouped summaries (getting syntax right) Determining

Key concepts

  • [L1, L2] Experiments and observational studies
  • [L1, L2] Samples and populations
  • [L2] Variable types: categorical (nominal/ordinal) and numeric (discrete/continuous)
  • [L3] Summary statistics: mean, median, percentile, IQR, SD, variance, correlation
  • [L3] Distribution properties: skewness, outliers, modes
  • [L3] Robustness of common summary statistics
  • [L3] Relationships: positive/negative; linear/nonlinear

About the test

  • 4-5 questions
  • Expect one challenge part, but otherwise very similar to homework problems and practice questions
  • 48 hours, open book, open note
  • Posit cloud project + fillable form
  • Revisions will be allowed to earn back credit
  • No collaboration
  • Do your own analysis/writing (no AI plagiarism)

STAT218