Reference Document

Also get the r squared value to determine how well the trendline fits the data. Ideally this should be as close to 1 as possible. R squareds below 0.9 aren’t very good. If you get an r squared below 0.9 you should consider re-doing your standard curve. Use Excel to solve the equation for “x” and use this equation so solve for your unknowns. ................
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