On average, which country user's spend the most time on social media? Which country's users spend the least time?

Can someone me with the property questions for 12 13 and 14 plz

How can you construct perpendicular lines and prove theorems about perpendicular lines

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