The owner of a computer repair shop has determined that their daily revenue has mean $7200 and standard deviation $1200. the daily revenue totals for the next 30 days will be monitored. what is the probability that the mean daily revenue for the next 30 days will exceed $7500? round to four decimal places. a. 0.9131 b. 0.0869 c. 0.9147 d. 0.0853

Ur environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 4.04.0 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 2525 samples is 4.44.4 ppm with a standard deviation of 0.80.8. assume the population is normally distributed. a level of significance of 0.020.02 will be used. make the decision to reject or fail to reject the null hypothesis. answer tables