Excel: Using LINEST function, Plotting agraph, Adding Error Bars

Raghav K Chhetri01/24/2009

Using LINEST function

NOTE: I mistakenly put (m) for the unit of time.

• Lets start with a tablefor time and velocity asshown on the right.

• LINEST functionreturns several outputs,so to begin with, select a2 by 5 array as shown.

Under the Insert Tab, select Function. Then, make theselections as shown below. Hit OK.

Select the y-values and x-values from the table.

Write ‘TRUE’ for the last two boxes. Hit OK.

Now, highlight the formula in the formula bar.

Press Ctrl+Shift simultaneously and hit Enter (Macusers, press Command and hit Enter)

Linest Function

• The array weselected earlieris now filledwith numbersas shown tothe right

• Lets see whatsome of thesenumbers mean

Linest Function

Plotting a graph• Select the x-column first.

Hold down the CRTL keyand select the y-columnnext.

• Choose XY scatter, undersubtype, select the first one asshown

Plotting a graph

• Give an appropriate titleto the graph

• Label the axes (Don’tforget the UNITS!!)

Plotting a graph

• Select ‘As new sheet’. Name the sheetappropriately.

Plotting a graph

• Highlight the data points, select ‘Add Trendline’

Plotting a graph

• Choose ‘Linear’ under‘Type’

• Select the options todisplay equation andR^2 value on chart

Adding Error BarsNow that we have the plot, lets add the error bars.

• Select the data points andright click

• Select ‘Format Data Series’

Adding Error Bars• Click on the ‘X Error Bar’

tab

• Select ‘Both’

• Under ‘Custom’, click on thewidget on the right of the +box

• Go back to the data sheetand select the uncertainty inx-values (next slide)

Adding Error Bars

• Select the uncertaintyas shown, then click onthe widget on the right

• Repeat the same forthe - box once donewith the + box

• This adds the errorbars in the X-direction

Adding Error Bars

• Repeat thesame procedurefor puttingerror bars in theY direction

• Once done,your graphshould look asshown to theright

The End.