Chart help - cannot display all data

[Fred]

Excel 2000

At various times during each day I have to measure my blood pressure. Each
time I take 4 readings (simplified version).

A: DATE B: TIME C: BP
A1: 01/01/2007 B1: 09:00 C1: 75
A2: 01/01/2007 B2: 09:01 C2: 77
A3: 01/01/2007 B3: 09:02 C3: 74
A4: 01/01/2007 B4: 09:03 C4: 77

I can generate a scatter chart with Days on the x axis, BP on the y axis and
the C data as vertical columns of short horizontal lines ( - ) for each day.

This method produces a good graphical representation of the range of the
day's readings, but multiple readings with the same value are only displayed
as a single point on the chart.

i.e. 1 off 74, 1 off 75 and 1 off 77

I still need to create a chart that will display every reading so I tried
using a helper column D with the values A+B i.e.

D1: 39083.375
D2: 39083.37569
D3: 39083.37639
D4: 39083.37708

I then used these values for the x axis and series range but this only
worked over a minute spread of D values before, once again, failing to
display multiple values correctly.

Quite probably a "senior moment", but any help would be greatly appreciated.

 

[Bernard Liengme]

Could you use date&time as the x-values?
With your present data, insert a new C column
In C1 enter =A1+B1 and format with Custom Format mm/dd/yy hh:mm (or dd/mm/yy
hh:mm if Canadian or British)
Now make an XY chart with columns B and C. It will look better with more
than 4 data points.
best wishes from (Old)Bernard

 

[Jon Peltier]

I then used these values for the x axis and series range but this only

worked over a minute spread of D values before, once again, failing to
display multiple values correctly.

If you have several values each day, but they are measured between 9:00 and
9:03, then when multiple days are included, the spread between 4
measurements in 3 minutes will be overwhelmed by the intervening 23 hours
and 57 minutes. Follow Bernard's suggestion (i.e., format your column D in
date + time format, and insert it before the BP measurements), then make
your chart; but where Bernard says XY chart, instead make a Line chart. Then
go to Chart menu > Chart Options > Axes tab, and under Category (X) Axis,
select Category.

- Jon

 

[Fred]

Could you use date&time as the x-values?
With your present data, insert a new C column
In C1 enter =A1+B1 and format with Custom Format mm/dd/yy hh:mm (or
dd/mm/yy hh:mm if Canadian or British)
Now make an XY chart with columns B and C. It will look better with more
than 4 data points.
best wishes from (Old)Bernard

Thanks for your prompt reply Bernard.

Your solution was effectively the same as the "simplified??" description in
my original post and thankfully confirmed that I was on the right track!

Armed with your confirmation I looked even more closely at my data and
realised, for the first time, that some of the time intervals (timestamped
automatically by my BP monitor) were well under a minute apart. This
explained why some of my chart points were a couple of pixels wider than the
norm as the points were being correctly plotted but on top of each other!

Manually editing the times to adjacent minute intervals solved my problem.

Thanks again for your help.

Regards,

 

[Fred]

If you have several values each day, but they are measured between 9:00
and 9:03, then when multiple days are included, the spread between 4
measurements in 3 minutes will be overwhelmed by the intervening 23 hours
and 57 minutes. Follow Bernard's suggestion (i.e., format your column D in
date + time format, and insert it before the BP measurements), then make
your chart; but where Bernard says XY chart, instead make a Line chart.
Then go to Chart menu > Chart Options > Axes tab, and under Category (X)
Axis, select Category.

- Jon

Thank you Jon for your prompt reply.

As per my reply to Bernard you will see that I have now solved this problem.

You are, of course, completely correct in saying that such small time
increments will be swamped. That was one of the reasons for my post - the
vain hope that one of you gurus had managed the impossible and found a way
of getting all this data onto a sheet of A4 paper!

I have resorted to using the Scatter chart in favour of the Line chart
because, over the last year, my GP has always visualised a trend line
through the middle of my Line chart and totally ignored the fact that the
upper and lower data limits are way outside spec! Now, when 6 of the 16
daily points are clearly above her "line", she cannot possibly deny the
tablets aren't working.

Surprisingly, I have found that a year's Scatter chart with this density of
data displays remarkably well when using 5pts sized data markers. I find
that it is more easily understood by a lay person (I am not referring to my
GP) because they can read off the actual numbers instead of looking at a
meaningless (to them) line zooming up and down across the page. It is also
easier for me to demonstrate an exact value at any point on the chart.

Thanks again for your expert help on these groups.

Regards,