Find the center line and control limits for each of the following situations.
a.* Percentage chart, sample size n = 300,  = 0:0731.
b. Percentage chart, sample size n = 450, = 0:1683.
c.* Percentage chart, sample size n = 800, = 0:0316, standard is π0 = 0:0350.
d. Percentage chart, sample size n = 1,500, standard is π0 = 0:01.