Please add error-bars to plots, tables, and values reported in the text. For example, the abstract now states "the size of the synthesized nanoparticles was 21.57 ". Cannot be so accurate! can anyone explain?
Romana Naaz The statement '"the size of the synthesized nanoparticles was 21.57" is nonsense. For a start - what are the units? Furthermore, try and understand how many decimal places can be reasonably quoted if the 'answer' (delivered by the computer!) was actually 21.57 nm. One way of thinking about this is to ask you a couple of questions:
- Is the 21.57 a mean (if so, what sort?), median or mode? Or just a single value?
- What was the technique used to derive the '21.57'? Relates to the parentheses in the last bullet point
- What is the diameter of a hydrogen atom?
It depends on how you obtained it. Also, if this is a mean, you should add the standard deviation and I personally limit it to the first non zero number of the standard dev. That means if my standard dev is 0.11 and the value from the mean is 21.57, I will report it as 21.6(0.1) [unit, whatever it is]. It is better to report a value less precise than what you could "obtain" than more precise than what you could obtain (i.e., I would prefer to overestimate my error than underestimate it. I will leave more room in my reported precision than less). The value of standard deviation and the mean, I will also make sure it is not appear more precise compared to what could be reasonably measured in my instrument. For example, If I estimated this from SEM with a certain scale bar, and then I just used a 100 nm or 200 nm or even a 50 nm scale bar, I would not even dare report a decimal and I would say it is ~20 nm. Maybe 20-30 or 20-25 nm if you like to say so. Of course that depends on the instrument used (some have been calibrated to a certain extent with standards). If It is from AFM, I would also consider the precision of my AFM instrument (could be based on the tip size also and the standard for calibration). If you used some spectroscopic means (or spectroscopic based), you have to think about how the size was obtained from the spectra or by the instrument and consider the derivation of the value (you will know then the estimation of uncertainties you have to consider).
In simple terms, the more digits you add after the decimal point refers that the value is that absolute, which is not correct in terms of nanoparticle sizes. The nanoparticles tend to agglomerate and thus have a varied range of particle sizes within a specific range and thus you need to add error bar which takes into account the standard deviation of the value mentioned. Also, it is better to report the nanoparticle size value up to a single decimal point with SD.
Hope this helps.
Romana Naaz Nine days have passed and we still do not have the answers to the 3 basic questions posed in my first response...
- Badges
- Science topic
- Similar topics
- Methodology
- Research Methodology
- Research Papers