Answer:
3) One-sided,compare two populations
Step-by-step explanation:
A manufacturer wants to investigate the whether there is an increase in the mean gas mileage of mid-sized sedan having new type of tire compared to mean gas mileage of mid-sized sedan not having new type of tire.
So, there are two populations :
population 1 : mid-sized sedan having new type of tire.
population 2 : mid-sized sedan not having new type of tire.
So, two populations are being compared.
Also, A manufacturer is investigating whether there is an increase in mean gas mileage.The alternative hypothesis will be right tailed and so, this corresponds to one sided test.