How you caluculate sensitivity and selectivity of Blast?
- 2 Answers
- 7687 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 are oesophageal molecular markers?
Describe the aim of microarray data analysis?
What is the difference in terms of connectivity between a scale free network and random network?
In the next two or three years what will the important advances in the field be?
Are all members of transporter families confined to a particular organelle or to the plasma membrane, or are some family members found throughout cellular compartments in eukaryotes?
Did bacteria, archaea, and eukaryotes exchange transporter genes appreciably during the past two billion years?
What is a homologue?
what is the principle involved in Biometry?
How to identify common acc.numbers from among a set of files ?
How will you value a biotech company as opposed to a consumer products company?
How can we find the direction of an nucleotide substitution, for example; C to T or T to C?
What is protein sequencing?
What does the ultrametric property of a tree tell us about the evolutionary process?
what is an active ? (UML)
Did integral membrane transport proteins arise as an independent protein class or from other types of proteins?
