What is the control group? Does the age groups 13-19 and 45-older peripheral Vision affected by their age?

In this test what would be the control group?|||In any objective scientific experiment, there is a test group and a control group. The control group is the same kind in terms of age, size, gender, location, etc as the test group. But the test group is affected by whatever is being tried out.





For example, pretend we believe that hearing is not affected by loud noise for one minute. Two groups of twenty people randomly selected are separated.





One is exposed to loud noise for one minute. This is the test group. The other group is not exposed to the loud noise. They are the control. If the control has better hearing than the test group after the loud noise for one minute, then the hypothesis is not proved and loud music does affect hearing.





In your question, people over 45 are indeed affected by loss of vision. It is normal and called presbyopia. Distance vision is usually not affected but close reading vision deteriorates.





In this case the control group is the younger group, as they are not affected by age; the hypothesis being: "ageing causes vision loss." In which case I am confident the hypothesis would be proved.