Question

Determine the area under the standard normal curve that lies left of z=0.54.

Answer 1

How . So confused

Answer 2

is is a lookup problem. Estimate first.

Left of any positive value is at least 50%, right?
1/2 Standard Deviation to the right, using the empirical rule, is about another 17%-ish.

When you look it up, or get your calculator to do it, you should get around 67% - maybe 68% or 69%.

Answer 3

Sorry, I was a little off, before.

One piece at a time. Do you understand that z = 0 corresponds to the Mean of the distribution and has 50% on each side. This is a good place to start.