Our environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 5.4 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 9 samples is 5.0 ppm with a variance of 0.64. assume the population is normally distributed. a level of significance of 0.02 will be used. find the value of the test statistic. round your answer to three decimal places.