Question $2$: The dataset $$CO$2$ includes the data of an experiment on the

cold tolerance of the grass species Echinochloa crus$-$galli. Use R to answer the

following questions based on this dataset.

$1.$ What are the types of plants?

$2.$ How many plants are of $$Quebec$$ types?

$3.$ Find the plants with ambient carbon dioxide concentrations less than $500$ mL L$?$

$4.$ Find the number of plants that are of $$Mississippi$$ type and $$nonchilled$$ treatment?

$5.$ Compute the mean carbon dioxide uptake rates for each type of plants.

$6.$ If ambient carbon dioxide concentrations is expected to be decreased by $14\%$ when the

experiment is repeated after $3$ months, estimate the concentrations for all plants after

$3$ months.

$7.$ Add the column that contains the ambient carbon dioxide concentrations after $3$

months that is computed in part $(6)$ and name it $$conc$14.$