There are 84 students in a speech contest. Yesterday, 1/3 students still haven't given their speeches?
of them gave their speeches. Today,
1/4 of the remaining students gave their speeches. How many students still haven't given their speeches?

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