Answer:
(ai) The correct answer is the first option; The amount of tax the student is willing to add to a gallon of gasoline.
(aii) The correct answer is the last option; Whether the student believes that global warming is a serious issue or not.
(b) The correct answer is the first option; two-sample t interval
Step-by-step explanation:
A response variable in statistics is the idea or concept of needs to be proven right or wrong. It remains a response variable until it has been proven.
An explanatory variable simply means an independent variable. It doesn't depend on any other variable and at the same time, it can be manipulated.
In construct a 95% confidence interval to compare the two groups, two-sample t test is the appropriate t test to use.
Yes. x=3 and y =9 are the solutions.
Because if you change x=3 and y =9 ,you will have
3+2* 9 =21
3+18 =21
21 =21 (true)
There are a total of 297 students in the 7th grade. Rough estimates would say that about half of that number are boys and half are girls. Asking only 50 random girls would be biased because not only would it not be all of the girls (the number of girls would be around 148 or 149) but it would also be ignoring the roughly 148 to 149 boys there are on estimate. The sample would be biased because it would be ignoring the opinions of more than half the seventh grade.
Answer:

Step-by-step explanation:
Given: 
To find: number which represents the expression
Solution:
Integers refers to natural numbers, 0 together with negative of rational numbers.
A rational number is the number of the form
where p and q are integers and
.

So,
represents 
Answer:
150 oz.
Step-by-step explanation:
There are already 150 ounces of alloy of nickel.
Of this 150 oz, 70% is pure i.e. nickel content = 150(0.7) = 105 oz
Now available is
Nickel Other metals
105 45
Let x oz of pure nickel is added.
Then new alloy will have 105+x oz nickel in total of 150+x oz.
Percentage pure = 
Simplify to get

Hence answer is 150 oz should be added.