PCED case studies
PCED · Put your knowledge to work in context.
PCED – Certified Entry-Level Data Analyst with Python is an entry-level Python Institute certification (exam code PCED-30-02, active since July 15, 2025) that confirms foundational knowledge of data analytics and Python programming. It is aimed at complete beginners, aspiring data analysts, students and career changers, professionals in non-technical roles, and educators who want a structured first credential in data work. The PCED case studies are 5 cases and about 2,869 words.
1Twelve Store Exports and the 18% Weekly Drop
You are preparing the quarterly sales dataset for a 12-store retail chain. Eleven stores upload UTF-8 comma-separated CSVs with ISO dates (YYYY-MM-DD).
661 words, about 3 min2Survey Wait Times: The Mean That Overstates
A community nonprofit ran a 240-person survey about wait times at a food pantry. The main field, response time seconds, is recorded automatically; 12 responses are blank (5%).
560 words, about 3 min3Open Dashboard, Small ZIP Counts, Rare Condition
A regional clinic wants to publish an open dashboard showing chronic-condition prevalence by ZIP code and age band. The dataset has 4,800 patients.
548 words, about 3 min4Nine Slices, a Truncated Axis, and a 'Best' Region
An analytics team is preparing a quarterly review for nine sales regions. A colleague proposes a 3D pie chart with nine slices to show each region's share of total revenue, and a second line chart with the y-axis starting at 80% of revenue to make the growth trend 'look clearer.' They also want to call out Region 4 as 'best' because it has the highest absolute revenue, although Region 7 has the fastest growth from a smaller base.
538 words, about 3 min5MemoryError on a 2.1-Million-Row Sensor CSV
You inherit a script that reads a 2.1-million-row, 14-column CSV of sensor readings (about 1.8 GB) on an 8 GB laptop. It opens the file with open(), uses csv.reader, appends every row to a list of dicts, then makes four separate passes over the list to compute min/max, group counts, and a daily average.
562 words, about 3 min