MS-EXCEL: GOING FURTHER WITH GRAPHS II: CALCULATING SLOPES

Plotting derived data

The investigation can be extended to determine the rates of photosynthesis at other concentrations of hydrogen carbonate solution.

The graph of each concentration needs to be inspected to determine where the slopes should be calculated.

The slopes are then calculated for each of the concentrations.

The number of decimal places is corrected.

A graph is then drawn of this derived data and trend line is fitted to it.

Notice the data for 0.0125 mol dm^-3 shows some divergence from the trend line. When the data is analysed it reveals that it is not very consistent. This is an indication that the experiment with this concentration should be repeated or it may be rejected. If rejected it would give a graph like the one below.

The problem is that this is a trend line from only four data points. This is not usually acceptable.

• Previous page
• Index Page
• Top of Page

© Paul Billiet 2007