This table shows the value of a computer as a function of time elapsed since the computer was manufactured. The value of the computer decreased exponentially throughout the five-year period. What was the average annual amount of decrease (in dollars per year) over the two-year interval t = 2 to t = 4 (Note: Give the answer as a positive value.)

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