Car manufacturers measure the length of time a car sits on the dealer’s lot prior to sale. Popular cars might only sit on average for 10 days, whereas overstocked models sit for months. This company...

Car manufacturers measure the length of time a car sits on the dealer’s lot prior to sale. Popular cars might only sit on average for 10 days, whereas overstocked models sit for months. This company collected data each month for the length of time cars sat on dealer lots for 10 models from 2002 to 2011.

(a) Identify whether the data are cross sectional or a time series.

(b) Give a name to each variable and indicate if the variable is categorical, ordinal, or numerical (if a variable is numerical, include its units if possible).

(c) List any concerns that you might have for the accuracy of the data.