In an experimental test of the effects of vitamin b-12 on problem-solving performance, is the independent variable and is the dependent variable.

vitamins, problem solving performance

Explanation:

In the given sentence - vitamin B-12 on problem-solving performance

vitamin is considered to be the independent variable and problem-solving performance is considered to be the dependent variable.  

As performance is dependent upon the intake of vitamin hence it is considered to be a dependent variable due to dependency on the vitamin. But on the other side vitamin is the independent variable as it does not depend on others.

the vitamin; problem-solving performance                                                              

Explanation:              

Independent variable: In psychological research, the term independent variable is defined as the variable that is being changed, altered, and manipulated in an experiment. Any change in the independent variable in an experiment will have a direct effect on the changes that occur to the dependent variable.

Dependent variable: In psychological research, the term dependent variable is defined as the variable that is being tested or measure in an experiment. The dependent variable in an experiment will change if any change in the independent variable is being identified.

can you explain it better

what's this it's not giving you what have to do.