Question

Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 6.6 parts/million (ppm). A researcher believes that the current ozone level is at an insufficient level. The mean of 980 samples is 6.5 ppm. Assume the standard deviation is known to be 1.1. Does the data support the claim at the 0.05 level?

Answer 1

We need to test if the current ozone level is insufficient. Hence, our hypotheses will be:

Ho: = 6.6

Ha: < 6.6 [Left - Tailed]

Test statistic

z = -2.846

p - Value = P(z < -2.846) = 0.0022

Since p - Value is less than 0.05, we reject the null hypothesis. Hence,

There is sufficient evidence to support the researcher's claim that the current ozone level is at an insufficient level.