mu = 1100 = population mean
sigma = 275 = population standard deviation
x = 1400 = raw score
z = z score
z = (x-mu)/sigma
z = (1400-1100)/(275)
z = 300/275
z = 1.0909090909091 approximately
z = 1.09
Convention is to round to two decimal places so that you can use a Z table to look up the area under the curve (which helps determine probability).
The positive z score is due to Paula's raw score being above the mean.
