How To Find Seasonal Index [updated] -

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Collect at least 3–5 years of data for the same period (e.g., monthly or quarterly). how to find seasonal index

📌 Example: If January’s average sales are 120 and the overall monthly average is 100, the seasonal index = 1.2 (20% above average). Here’s a clear, professional post you can use

Calculate the grand mean of all data points across all periods. Here’s a clear