Question

Explain to your classmate's what a null-hypothesis. How do you make the decision to reject or not reject a Null-Hypothesis? What are some examples? All work must be in your own words.

Answer 1

A statistical hypothesis is an assumption about a population parameter. This assumption may or may not be true.

• Null hypothesis:The null hypothesis, denoted by Ho, is usually the hypothesis that sample observations result purely from chance. It is the hypothesis the analyst believes to be true.
• Alternative hypothesis:The alternative hypothesis, denoted by H1 or Ha, is the hypothesis that sample observations are influenced by some non-random cause and analyst believes it not to be true.
• By conducting statistical experiments, (called hypothesis testing) we can accept (fail to reject) or reject the null hypothesis. According to p-value we can accept or reject null hypothesis that is p-value < alpha then we reject null hypothesis, otherwise accept it.

Examples:

Question 1:Does taking aspirin daily reduce the chance of having a heart attack?

Null hypothesis: Taking aspirin daily does not affect heart attack risk.

Question 2: Does eating more fruits, will help in weight lose faster?

Null hypothesis: Eating more fruits does not help in faster weight loss.