Question

Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 4.2 parts/million (ppm). A researcher believes that the current ozone level is at an excess level. The mean of 920 samples is 4.3 ppm. Assume a population standard deviation of 1.2. Does the data support the researcher's claim at the 0.05 level? Step 4 of 6 : Find the P-value of the test statistic. Round your answer to four decimal places.

Answer 1

Solution :

This is the right tailed test .

The null and alternative hypothesis is ,

H0 :   =4.2

Ha : >4.2

Test statistic = z

= ( - ) / / n

= (4.3-4.2) / 1.2/ 920

Test statistic = 2.5

P(z >2.5 ) = 1 - P(z <2.5 ) = 1-0.9938=0.0062

P-value = 0.0062