In this video we solve 2 exercises that require the use of the T test. Remember, the T test is used when the sample size, n, is less than 30 and if the population variance is unknown.
Thanks for your question! I understand the confusion as this question's phrasing is tricky and meant to truly test your understanding. The question initially states that the mean weight is intended to be 5g i.e H0: = 5g. Then, it tells us to test this H0 and prove its not above 5g, which is the same as telling us to prove H1 is false. Therefore, H1 would be stating that the mean weight is > 5g. If we had rejected H0 (hence accepting H1), it would mean that the mean weight IS higher than 5g. However, because we failed to reject H0, it means we reject H1, hence showing that the mean weight of tablets ISN'T above 5g.
If the problem does not say is normally distributed we can use the Z or t formula. Is what my Dr said in our class. I dont know which is which. Can you pls expain for me
This is because in the question, we know for a fact that the car journey to work originally took 42 minutes - therefore H0=42. On the other hand, it then says that after the road layout being altered, Celia believes that this has INCREASED the journey time - hence H1 > 42.
