This is inconsistent with the quiz
For the quiz, we wanted test "If I am taller than the average", and yet, the alternative hypothesis was "I am taller" not the null.
Here, we want to test if "the average is 70%", and that's our null.
If the null hypothesis is what we want to reject, shouldn't "the average is 70%" be our alternative?
@Abdulmalik Alkhamis. I know this answer might be coming in quite late. However, this is for anyone with similar confusion.
Question.
You want to check if your height is above average, compared to your
classmates. State the null and alternative hypotheses of this test.
H0; This is what is generally held true until proven otherwise. If you want to prove that you are taller than the person with the mean height in your class you have to assume that you are not taller than the person with the mean height until you can prove the contrary.
H1; This is the statement the contender, researcher or opposer is trying to prove. This is contrary to the null hypothesis. In the context of our example, that will be the statement "I am taller than the person with the mean height in my class".
Hope this helps.