Error Bars on Graphs

[ivy12003]

Okay, so for biology and chemistry, we haven't really been taught about error bars and how to use them on graphs... and we've already completed several labs. Will I be penalized for not having them since I haven't learned them yet?

[moneyfaery]

Doubt it. They're nice to include but not mandatory. If you want to include them for subsequent labs though, download Graph (http://www.padowan.dk/graph/) - it's a smooth, clean piece of code that runs nicely. Or you could use Excel but its trendlines are terrible.

[tirentu]

I can't really say for Bio or Chem, but in Physics error bars are expected. They factor very minimally into the marking of graphs, but I have been penalized before for not including them.

[moneyfaery]

I can't really say for Bio or Chem, but in Physics error bars are expected. They factor very minimally into the marking of graphs, but I have been penalized before for not including them.

By your teacher or by IB? I would think teachers are more likely to penalize students for such things because you always have the chance to improve. Although since it's expected, I guess IB could penalize you as well.

[dexter]

But how do you add them on excel?? I tried but dont know how to also I was wondering, If you have a bar graph and for example the x axis is temp your reading are for 20 C , 40 C , and 70 C , are you suppose to make equal distance on the x axis (scale ) when i in put the data it just gives me three bars, what i mean is there suppose to be a scale when using bar graphs even if your data recorded arent in equal intervals??

[moneyfaery]

Use Graph (http://www.padowan.dk/graph/) and input the error values manually. Excel seems to only sets fixed values/percentages for errors. What I gathered from a brief glimpse anyway.

[avrila]

Okay, so for biology and chemistry, we haven't really been taught about error bars and how to use them on graphs... and we've already completed several labs. Will I be penalized for not having them since I haven't learned them yet?

I suggest you to have it in your graph. I also didn't learn it from my teacher instead have to learn by myself as my teacher was not around at that time to teach us. If you want to have a good mark in lab report, include the error bars. I just use excel. It's not that hard and after several lab reports, you will get used to eat. At first, ya.. it took times. You need to try an error. Good Luck!

[KiwiFruit]

Our teacher at our schools says they are very important, he wont give us a 2 for the section without them. He says either standard deviations, 95% confidence levels. You said you havnt been taught, just because your not taught them doesnt mean IB doesnt want them. Put them in and be the star of your class. Look on the internet for advice its not really hard.

www.psych.ubc.ca/~emmab/How_to_do_error_bars.doc

Check that out,

Have a merry christmas

[hermine0817]

Use Graph (http://www.padowan.dk/graph/) and input the error values manually. Excel seems to only sets fixed values/percentages for errors. What I gathered from a brief glimpse anyway.

Naah, you can put error bars using excel as well. When you have a line graph, you can double click the dots and a window pops up. Select the third feature which says "y-error bars" and then, you can either make your errors as fixed values/percentage/ or even whatever you like. The last option would be to customize and there, you can easily scroll sections from your table into the error bar section. (I have MS Office 2003 though, so no idea how to do it in 2007)

Moreover, in my school, in chemistry and biology, it is not that important to include error bars, but you get penalized for not including it in physics. Moreover, according to my teacher, the graph shouldn't be too small, else it will be hard to recognize the margins, errors etc, so make it at least a third to half a page big on MS Word. (He is very picky and would write in red that your graph is too small, but he hasn't so far penalized us yet. But he is getting stricter with his grading nowadays, so it might happen that we will get penalized somewhen....)

[Pod]

If you have excel 2007, it is really easy to input the error bars. Once you have your graphs go to design (or insert not sure) and you should have error bars tab. Click on it and insert error bars. the catch however, is that sometimes, excel inputs the error that I don't want (well to me anyways) and you can change it by manually inputting your errors.

[SamP]

Use excel 07. Really fast to learn and use.