I am learning algorithms from the clrs book. I am having trouble understanding the notation the book has placed. The book wrote the following: $t_j$ denote the number of times the while loop test in line 5 is executed for that value of $j$.So does that mean $t_2$ would represent the entire set time the while loop was hit when $j = 2$? 
Clarification notation in CLRS runtime analysis
algorithm analysis;notation
The number of iterations of the while-loop depends on j which changes during across iterations of the for-loop. Thus, the total runtime of lines 5-7 must depend on $j$, and the runtime of lines 6-7 may depend on $i$ (it does not here).I can add nothing more over the quote you give; $t_2$ is the number of times line 5 is reached during the for-iteration with $j=2$, indeed.Our reference question shows you how to obtain such formulae in a structured way. Try to follow the techniques from a blank start and you will see how this comes about.