Final answer:
To find the slope from CPI values in Excel, plot the values on a scatter plot, add a trendline with the equation displayed and note the coefficient of 'x' as the slope. Alternatively, use the SLOPE function with CPI as Y values and time as X values.
Step-by-step explanation:
To find the slope in Excel from CPI values, you can perform a regression analysis using the built-in functions. Here's a step-by-step guide:
- Collect the CPI values and the corresponding time periods (years).
- Enter the time periods in one column (X-axis values) and the CPI values in the adjacent column (Y-axis values).
- Plot a scatter plot of the data with time on the X-axis and CPI on the Y-axis.
- Use the TRENDLINE function, which can be added through the chart elements option in Excel, to create a least-squares regression line.
- Format the trendline to display the equation on the chart. The equation will be in the form y = mx + b, where m represents the slope.
- The slope (m) in the equation indicates how the CPI value changes with each period. A positive slope means an increase over time, and a negative slope means a decrease.
The slope can also be calculated manually using the SLOPE function in Excel, by entering the range of Y values and the range of X values as arguments.