A T-Test checks if two averages (means) are really different , or if the difference is just due to random chance . Find the Averages You get some sales numbers: Region A : 210, 220, 215, 225, 230 → 👉 Average = 220 Region B : 195, 200, 190, 205, 198 → 👉 Average = 197.6 There’s a difference. But is that difference big enough to matter? 🎯 Step 2: Check How Spread Out the Data Is (Variance) Are all sales close to the average? (Low variance) Or are they all over the place? (High variance) More spread = more uncertainty. 🎯 Step 3: Use the T-Test Formula Now the t-test combines: The difference in averages The amount of spread (variance) How many data points you have And gives you a T-Value (a number like 2.5 or 5.1). 🎯 Step 4: Convert T-Value to P-Value The computer or calculator turns the T-Value into a P-Value . If p < 0.05 → 🟢 There's a real difference If p > 0.05 → 🔴 The difference might be just by chance 🎉 Example Summary RegionAverage SalesRegion A220Region B19...