calculate mean Phred scores from list of Q values

This method calculates the mean quality value from a list of q-values; handles the challenge of relative log-scaling of the Q and challenges of a more linear mean; this avoids an artificial inflation of phred-scores

phredmean(q)

Arguments

q	is a vector of q values

Value

mean phred scaled q-value

Examples

mean(c(20,30,40))
#> [1] 30
phredmean(c(20,30,40))
#> [1] 24.31798