Answer: 3) Confounding variable
Explanation:Confounding variable is the variable that indicates about the external influential factors that produces the manipulated consequences of independent and dependent variable.This variable can lead to producing useless outcomes in an experiment.
According to the question, the changes occurring in interest of student in algebra can be due to the outside factors which are not generating the actual results and thus, experiment is getting ruined.
Other options are incorrect because application variable remain same for the experiment,system variable are the variables of certain system and reliability variables describe about the variable on which dependent or stable.Thus, the correct option is option(3)
Resources can include things that are material, like having water or grain to use in production. They can also include human resources, such as having enough employees or having employees with education or skills to do particular tasks. Resources can also be abstract, such as having money (capital) to invest in business or having good relationships (social capital) with suppliers or government officials.
