Hi all,
I want to calculate fluorescence intensity among 3 samples from image J. I have 3 different concentrations of a compound in 1hr time period. I want to see which concentration is working best in 1hour time period. I have dapi and GFP signal for cells and drug respectively. I didn't take the control as it don't have any GFP signal or untreated. Now I took individual cells from different field of 1 well and calculate mean intensity from image J. you can see my raw data from my excel file. But I'm struggling how to calculate SD, SE and t.test value from my data and also want to plot the bar graph to see which concentration should I take. In my case SD should be stdev.p value or stdev.s value? and what is the formula of t.test value r p value? Thank you very much in advance if someone can help me regarding this.
ImageJ only measures intensities; it doesn't perform advanced statistics. Export to Excel/R/Python to calculate SD, SE, and t-tests. In this case, no concentration is statistically superior, although concentration 25 has the highest mean.
1. Measure Intensity in ImageJ
• Use ROIs → Analyze > Measure → Export Mean Gray Value or Integrated Density.
2. Calculate in Excel (or similar software)
• SD (Standard Deviation):
=STDEV.S(data range)
• SE (Standard Error):
=STDEV.S(data range)/SQRT(COUNT(data range))
• t-test / p-value:
=T.TEST(group1, group2, 2, 2)
3. Interpret & Visualize
• Use SE or SD as error bars in graphs.
• A p-value < 0.05 typically indicates statistical significance.
Maha Fouad Ahmad Thank you so much for the answer. Its completely detailed as I need. But one doubt regarding the p value/ t.test value. Why you used tail and type value 2,2. How can I decide this value? Because in my case 3 different concentrations so I think I need to use 2 and 3. How should I decide the tail and type value in t.test?
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