Problem:Probability of Type I Error

Null:u>=50

Alt: u<50

.025 for level of sig.

var=16

Assume n=16 and the true mean=50.5

I am really not sure how to solve this as our ex. refer to the null hypothesis as being less than or equal to.

For example do i start like:

C={Xbar; (Xbar-50)/(4/sqrt16)}={Xbar-50>c}

C={Xbar; Xbar>50+1.96} (c=1.96)

P{Z> (51.96-50.5)}...?

Any help is greatly appreciated.