refers to the degree to which changes in the dependent variable are due to the manipulation of the independent variable.

Internal validity

Step-by-step explanation:

Internal validity is a scientific study that emphasize on the fact that there is a proof to validate a specific study. Let's say i'm a forensics scientist for example; and there was a recent crime scene in some nearby sub-urban area which demands our call, when present at the scene, The main task there is to gather information as much as we can  which is required to be investigate in the laboratory for further analysis.The process of information gathering is our independent variables which varies with different causes of the crime, the laboratory analysis that make deductions (which is cause by some manipulation) of the information gathered is our dependent variables.

Therefore, we can conclude that Internal validity refers to the degree to which changes in the dependent variable are due to the manipulation of the independent variable.

Internal vadility

Step-by-step explanation:

Internal validity is the accuracy of evidence from experiments or investigation showing that your research methods were done properly.

Internal validity increases when there is less of confounding in your research methods.

1/3 + 1/3 ≠ 2/6 because 1/3 alone = 2/6  

step by step explanation:

1/3 + 1/3 = 2/3       2/3=4/6