Question 1128016
z=(x-mean)/sd
a.  z=(4-4.9)/1.9=-0.47
probability z>-0.47 is 0.6808
b. this is a z between -1.9/1.9 or -1 and .1/1.9 or 0.05
probability is z between -1 and 0.05, or 0.3613
c. 97th percentile is z>1.88 
1.88=(x-4.9)/1.9
=8.47 years
d. This is a z> (4.5-4.9)/1.9/sqrt(35), sampling distribution of sample means.
z> -0.4*sqrt(35)/1.9=-1.25
probability is 0.8944