Answer: -1.5
Step-by-step explanation:
When population standard deviation is known, then the formula to find the z-test statistic for population mean is given by :-
, where n= Sample size.
= Population mean
= Sample mean
= Population standard deviation.
As per given , we have 
(average infants contracted typhoid each month)
n= 4 (No. of months)
Then , the value of the appropriate test statistic will be :
Hence, the value of the test statistic = -1.5
Normally you would divide something like this by the cuts made. So if there were cuts of 2 inches on a 10 inch rope, then you should divide 10 by 2. It's the same with this:
Multiply by the reciprocal when you are dividing fractions.
1/9 = .1 repeating because 1 divided by 9 is .1 repeating
C
It would also be in Quadrend 1
