Answer the following and illustrate each under the normal curve.

1. Compute the probability area to the left of z= -1.25
2. Find the 90th percentile of a normal curve.
3. find the probability area between z =-0.25 and z=1.5
4. In one Barangay of South Cotabato, there are 500 families who are members of SAP. Their mean of family is 6 with a standard deviation of 2.

a. How many families have 4 to 11 members?

b. Find the percentage of families with more than 9