How you caluculate sensitivity and selectivity of Blast?
Answer Posted / rishu
Suppose the Blast search returned 100 hits. Of these, 17
were false positives and we knew that there were 165
sequences in
the database which should have returned a hit with our
sequence.
To calculate the sensitivity and selectivity, we must
determine the number of true positives (ntp), the number of
false
positives (nfp) and the number of false negatives (nfn). We
are told that the number of false positives was 17, hence
the
number true positives must have been 100-17 = 83, as there
were 100 hits. Therefore we know that the search algorithm
found
83 of the 165 sequences it should have found, hence the
number of false negatives was 165-83 = 82. So, we know that
ntp = 83,
nfp = 17 and nfn=82. Using the equations in the notes, we
can calculate:
Sensitivity = ntp/(ntp+nfn) = 83/(83+82) = 83/165 = 0.50 (2
d.p)
Selectivity = ntp/(ntp+nfp) = 83/(83+17) = 83/100 = 0.83
| Is This Answer Correct ? | 14 Yes | 0 No |
Post New Answer View All Answers
How do you find the most recent human sequence data in the data bases inorder to determine physical maps?
what is the image of point (3,8) in the line x + 3y = 7 ?
What two possibilities are there to describe how gene fragments may have evolved?
How to find flanking region ?
Can independent origins be established for two families of transport systems having no sequence or motif similarities without three-dimensional structural data?
Integrate 3x + 5 / (x3-x2-x+1)?
What is computational biology?
What does the ultrametric property of a tree tell us about the evolutionary process?
What are oesophageal molecular markers?
NLO : RPS : : ? : ZXA
Is there is best online Training for Bioinformatics
What are the bioinformatic tools applied to micromolecular evolution?
In the next two or three years what will the important advances in the field be?
What are the current challenges in the Pharmaceutical and biotechnology sectors?
What do you think are the more interesting areas of bioinformatics?