Sales are stable, not trending — a steady baseline
with sharp, predictable seasonal spikes rather than sustained growth or
decline across 2010–2012.
Dec is the seasonal peak month, with the largest
average weekly sales of the year.
Holiday weeks carry a statistically significant
lift of roughly 7.8% over non-holiday weeks (Welch t-test, p
< 0.01).
Store performance is highly uneven — a wide gap
separates the top store (Store 20) from the lowest-volume store (Store
33), pointing to structural rather than purely operational causes.
Macroeconomic indicators (temperature, fuel price, CPI,
unemployment) show negligible correlation with weekly sales in
this dataset — seasonal and holiday timing are far stronger, more
actionable signals.
Recommendations
Align inventory and staffing with the seasonal
calendar, concentrating resources ahead of the
November–December peak.
Model holiday weeks as a distinct forecasting
category with a dedicated uplift factor rather than the general
weekly average.
Investigate root causes at bottom-performing stores
— store size, local market density, and competition — before applying a
chain-wide fix.
Tighten forecasting cycles for high-volatility
stores, where week-to-week swings are largest relative to their
own baseline.
De-prioritize macroeconomic indicators in short-term
forecasting, given their negligible correlation with sales;
revisit for longer-horizon models only.
Extend this work with a formal time-series model
(ETS, ARIMA, or Prophet) per store, using the seasonal and holiday
signal identified here.
Row
Data source: Walmart Sales dataset (Kaggle) · Period: February 2010 –
October 2012 · Dashboard built in R with flexdashboard, plotly, and
DT