What is the effect of different concentrations of a pesticide on plant height?

What is the independent variable in the above question?

A car salesman records information about the cars he is selling.

The number of doors is _____ data

A car salesman records information about the cars he is selling.

The colour of each car is _____ data

A shop owner records information about his customers.

The method of transport is _____ data

A shop owner records information about his customers.

The average amount of money spent is _____ data

The number of seats in a car is _____ data

All 30 people leaving at the end of a Manchester City game are asked about their favourite football team.

This is a _____ of all the football supporters in the country.

Researchers want to test the effect of a mouthwash on how white teeth are. They make a scale of whiteness from 1 to 10 with 10 being the whitest. What type of data is this?

Over many hundreds of years, a population of rabbits living in the woods adapts to its surrounding with brown fur.

You accidentally touch a hot burner and quickly pull your hand away. The burner is

______________ means that conditions inside our body are kept stable (the same)

Dr. Jackson is making observations at Davisville High School to investigate the rate of smoking among American teenagers. Dr. Jackson decides she will observe students having their lunch in the parking lot where smoking is permitted. Dr. Jackson observes 25 out of 30 students smoking in the parking lot. Based on her observations she records that 83.3% of American teenagers smoke. What is the problem with her experiment?

Are you allowed to say that you proved your hypothesis correct?