Math Help - Help me with this please?

1. Help me with this please?

I am doing normal probability problems for a college statistics class. where i have to find Z. some of the problems require me to take one number from a table and subtract it from another number from the table. how do i know what order the numbers go? here is a sample

p(0.21<Z<1.69 ) the numbers in the tables are 0.5832 and 0.9545 i am supposed to take one number and subtract it from a nother

2. It depends

It depends on what your table gives. Are the entries
$Pr(Z
or $Pr(-z
In the former, the entry for z=0 should be 0.5; in the latter, the entry for z=0 is 0.

In the first case, to get $Pr(0.21, we use $Pr(0.21.
In the second, $Pr(0.21

Most tables i've seen use the first, but I've encountered a couple with the latter.

--Kevin C.