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.
Answer:
25%
Step-by-step explanation:
The percent of increase can be calculated using following formula:

In your case,
- Initial amount = 12 students;
- Final amount = 15 students,
then

Answer:
i have made it in above picture
We will define the following variables to solve the problem:
x = amount of round trips from 10 tons truck
y = amount of round trips from 12 tons truck
We write the system of equations:
x + y = 20
10x + 12y = 226
The solution to the system of equations is:
x = 7
y = 13
Answer:
10 tons truck makes 7 round trips
12 tons truck makes 13 round trips