drawing error bars from standard deviation urgent!!

pls help. say ive got an sd of 5. does this mean that on the point i plot on the graph the error bars will be +/- 5 or +/- 2.5

Reply 1

mqb2766

Original post by twinkle_31

pls help. say ive got an sd of 5. does this mean that on the point i plot on the graph the error bars will be +/- 5 or +/- 2.5

Sometimes the error bars represent 95% confidence intervals and so are +/-2 standard errors. What does the data represent and what are you trying to signify with the error bars?

Reply 2

twinkle_31

Original post by mqb2766

Sometimes the error bars represent 95% confidence intervals and so are +/-2 standard errors. What does the data represent and what are you trying to signify with the error bars?

im plotting a graph of percentage transmission and my teacher told me i had to add error bars bc it looks like the data might not be statistically significant so i thoight the easiest thing to do would be to use sd

Reply 3

mqb2766

Original post by twinkle_31

No real knowledge of this, but I guess its this experiment
https://qualifications.pearson.com/content/dam/pdf/A%20Level/biology-b/2015/teaching-and-learning-materials/AS-and-A-level-Biology-B-Core-Practical-5---beetroot-membrane-(Student,-Teacher,-Technician-Worksheets).pdf
If so, they mention the error bar on page 4 and refer to it meaning the min/max range (like a box plot), rather than std dev. However, I doubt its that significant as long as you explain clearly what youve done.

Reply 4

RobertMills

When dealing with standard deviation (SD), it represents the average amount of variation or dispersion in a set of data points. Specifically, if your SD is 5, it means that the spread of your data points around the mean is approximately 5 units.

Now, regarding error bars on a graph, they typically represent the variability or uncertainty in the data. Error bars usually extend above and below each plotted point to show the range of possible values.

In your case, if the SD is 5, error bars would typically be drawn at +/- 5 units from each plotted point to represent the variability in the data. However, it's essential to note that error bar length can depend on the context and the specific conventions or standards being followed.