Rewriting the left-hand side as follows,

Answer:
1. single sample design
2. matched pairs
3. two independent samples.
Step-by-step explanation:
the response variable is known as the dependent variable, it is the variable that the researcher is interested i finding. the response variable is the x variable that responds to changes in the independent variable.
1.
In this question the researcher has only one sample that is the specimen. that is the reference specimen that she obtained. Therefore it is a single sample design.
the response variable here is the measurement of concentration.
2. In this question we have two pairs, men and women. The researcher is interested in comparing attitudes as she interviews them. so response variable is attitude or behavior
3. this is a 2 independent sample design. The researcher is using two different methods to test and their average is being compared.
42 is the answer
Explanation:
50% of 80 is half of 80 which is 40
Then you would add 40 with 5% of 40
What you would do then is 5% times 40 then you would change the 5% into a decimal which is 0.05 and multiply it by 40 , which would get u 2
Then you would add the price with tax
40+2 = 42