Identify the following data as either time series or cross-sectional. (a) the 2017 ceo compensation of the 500 largest u. s. companies. (b) the annual compensation for the ceo of coca-cola enterprises from 2010 to 2017. (c) the weekly revenue for a noodles & company restaurant for the 52 weeks in 2017. (d) the number of skiers on the mountain on christmas day 2017 at each of the ski mountains owned by vail resorts.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)