#load required libraries
library(ggplot2)
library(dplyr)
#store the original measurements
pr<-c('P0','P1','P2','P3','P4','P5','P6')
t1<-c(0,49,56,52,266,225,306)
t2<-c(0,50,50,51,277,NA, 326)
t3<-c(0,48,53,56,273,209,316)
#combine the data into one tibble
dataMain<-tibble(pr,t1,t2,t3)
#re-store the data in a tibble containing the average across each row, removing the NA value where needed.
data<-dataMain %>% rowwise() %>% mutate(avg=mean(c(t1,t2,t3), na.rm=T))
#initialize the bar chart with ggplot2
bar<-ggplot(data, aes(x=pr, y=avg)) +
geom_bar(stat="identity")
#draw the plot
bar