Question

Acid rain – rain with a pH value less than 5.7 caused by the reaction of certain air pollutants with rainwater – is a growing problem in the US.

Suppose a sample of n = 40 rainfalls produced pH readings with a sample mean of 3.7 and a sample standard deviation of .5

A) Write the null and alternative hypothesis for this problem.

B) The data for the z-test is shown here. What is your conclusion? Support your answer with the appropriate statistics.

Data  
Null Hypothesis   5.7
Level of Significance   0.05
Sample Size   40
Sample Mean   3.7
Standard Deviation   0.5
  
Intermediate Calculations  
Standard Error of the Mean   0.08
z Test Statistic   -25.2982
  
Two-Tail Test  
Lower Critical Value   -1.96
Upper Critical Value   1.96
p-Value   -
  
One-Tail Test (Upper)  
Critical Value   1.6449
p-Value   -
  
One-Tail Test (Lower)  
Critical Value   -1.6449
p-Value   -

Answer 1