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    • Thread Starter

    Hey everyone, for my biology coursework I need help creating a simple bar chart, but with error bars/standard deviation included. I'm struggling to do this in word/excel and was wondering if anyone could help.

    All I need is two bars, each showing the average change in blood pressure from two groups, one is after liquorice consumption with the other after consumption of a placebo sweet.

    The changes are:
    Liquorice 1.4167
    Placebo 0.583

    I'm not sure how to work out/implement the error bars. Do I need to calculate standard deviation using a formula? Or do I just put on the range difference, i.e. the lowest and highest change, if you get what I mean.

    Any help would be greatly appreciated. Thanks
    • PS Reviewer

    PS Reviewer
    What data do you have so far? Is there a requirement somewhere to use SD over range bars? Both are possible but obviously range bars are easier to do. It is entirely possible in Excel! What would be easier is to use a forest plot rather than a bar chart. This would use the value of 1 to be blood pressure of controls (not taking anything), and then the relative increases/decreases in BP after taking the placebo and liquorice around that value. That method also allows you to see if your results are statistically significant: if one of your error bars overlaps 1, then the true effect could actually be nothing.

    If you want to use that method, I know how to make it on Excel and can give you a guide. Otherwise, I can also give you a guide on how to overlay error bars onto a bar chart Let me know!
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