Add them all up so it would equal 146.06
0 = 0
The input is an identity: it is true for all values
Answer: 68
Step-by-step explanation:
As per given , we have
Population standard deviation : 
Critical value for 90% confidence interval =
Margin of error : E= 0.8 milligrams
The formula to find the sample size is given by :-

i.e. 

Hence, the limnologist must analyze 68 samples.
The cheapest service would be the year in which the mean was the lowest. In Year 4, the mean was the lowest.
The most consistent service would be the year in which the range was the lowest. In Year 3, the range was the lowest.