Interested to Buy Any Domain ? << Click Here >> for more details...
How you caluculate sensitivity and selectivity of Blast?
- 2 Answers
- 8595 Views
- I also Faced
- E-Mail Answers
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
What is a DNA array?
In the next two or three years what will the important advances in the field be?
How can we find the direction of an nucleotide substitution, for example; C to T or T to C?
what is an active ? (UML)
Why do you think that bioinformatics is important?
What is C-compliator?
How the Algorithm works?
What are oesophageal molecular markers?
What is the idea behind ?weighting? sequences in the package CLUSTAL W for multiple alignment? How are these weights calculated?
What is computational biology?
A certain radioactive element A, has a half life = t seconds. In (t/2) seconds the fraction of the initial quantity of the element so far decayed is nearly how much?
Integrate 3x + 5 / (x3-x2-x+1)?
What is the input and outpit of a distance based algorithm?
what is the image of point (3,8) in the line x + 3y = 7 ?
Bootstrap analysis evaluates evolutionary trees by sampling columns from the original alignment with replacement (multiplying or removing some of them) and computing a proportion of times that a particular branch appears in the resulting trees. What is the main idea behind this approach?
