$1.$ Explain the difference between qualitative and quantitative variables. Give an example of qualitative and quantitative variables.

$2.$ Explain the difference between a sample and a population.

$3.$ For the following situations, would you collect information using a sample or a population? Why?

a$.$ Statistics $201$ is a course taught at a university. Professor Rauch has taught nearly $1,500$ students in the course over the past $5$ years. You would like to know the average grade for the course.

b$.$ As part of a research project, you need to report the average profit as a percentage of revenue for the #$1-$ranked corporation in the Fortune $500$ for each of the last $10$ years.

c$.$ You are looking forward to graduation and your first job as a salesperson for one of five large pharmaceutical corporations. Planning for your interviews, you will need to know about each company$$s mission, profitability, products, and markets.

d$.$ You are shopping for a new car and you started calculating how many miles per gallon $($MPG$)$ a car drives. You would like to estimate the typical gas consumption for a typical car.

$4.$ The following chart depicts the earnings in billions of dollars for ExxonMobil for the period $2005$ until $2018.$ Write a brief report discussing the earnings at ExxonMobil during the period. Was one year higher than the others? Did the earnings increase, decrease, or stay the same over the period?