Find the population standard deviation of the data set. 150 142 178 135 184 168 173 135 193

First find the mean This is 162.

Then work out deviations from the mean:-

= -27,-27,-20,-12,6,11,16,22,31

Square these values:- = 729,729,400,144,36,121,256,484,961

Add these up and divide the total by the number of values (9)

= 3860 / 9 = 428.888

Population standard deviation = square root of 428.888 = 20.71 to nearest hundredth (answer)

one fourth of 9% = 2.25%

gavin is correct in saying : the equivalent quarterly interest rate would be

2.25%.