A conclusion is valid it follows logically from the reasons – the evidence given to support it.
Steps involved in making a valid conclusion.
1) Ask a question.
2) Formulate a hypothesis.
3) Design an experiment to test your hypothesis.
4) Conduct an experiment to test your hypothesis and collect the data.
5) Analyze data.
6) Make a tentative conclusion.
7) Test your conclusion, or refine the question, and go through each step again.