Experimental design I think I have these answered correctly

Experimental design....

I think I have these answered correctly for the most part but I want to be sure. It\'s been a while since I had to look at this stuff!

English Ivy is an introduced species of ornamental plant in the United States. It typically grows in disturbed areas like roadsides. The sizes of leaves of English lvy are thought to be affected by the level oflight in the area they grow.Agroup of student\'s set-up an experiment to determine howlight level affects leaf diameter Three different light levels were used. Nutrient levels and amount ofwatereach plant received was kept the same. Independent variable: Dependent variable: Controlled Variables: Treatments: Individuals who participate in cardio exercise more frequently should have afaster heart rate recovery time than individuals who exercise less or not at all. A group of participants varying in their exercise frequency were asked to exercise for 5minutes by stepping up and down on a stair. The rate ofsteppingwas kept the same between each participant. Each participant took his or her resting heart rate before beginning to exercise, Atthe end of the 5min exercise period, participants recorded their heart rate, Then, Participants recorded their heart rate every 30 seconds until their heartrate returned to normal resting rate. All participants measured their heartrate using their radial artery and counting the number of bpm. Independent variable: Dependent variable: Controlled Variables: Treatments: Rivers are subject to high pollution rates due to runoff ofharmful chemicals, especially in more urban areas or areas that are frequently farmed, Many people think that rivers with more vegetation along the river bank (riparian vegetation) have less amount of pollution because the presence of vegetation can ease or prevent runoff. n order to test this, three areas along a river were chosen Ci) heavy amount of riparian veg, 2) moderate to light amount of veg, 3)no veg), Pollution rates were measured downstream of each area. Each area ofthe river was located along a major highway through the same city Independent variable: Dependent variable: Controlled Variables: Treatments:

Solution

First experiment:

Independent variables: light levels; this is changing in the experiment

Dependent variables: leaf diameter; depending on the Independent variables

Controlled variables: nutrient level and amount of water; not changing in experiment

Treatments: three different light levels

Second experiment:

Independent variables: time

Dependent variables: heart rate, radial artery pulse

Controlled variables: rate of skipping

Treatments: 5 minutes, 30 seconds

Third experiment:

Independent variables: Vegetations

Dependent variables: rate of pollutions

Controlled variables: highway area, harmful chemicals

Treatments: amount of vegetations