The data are reported in the attached table.
We define the null hypothesis H₀ as the statement that is believed true until we prove it wrong with the test.
We define the alternative hypothesis H₁ as the statement we want to conclude with our test.
The difference in graffiti before (B) and after (A) will be:
d = A - B.
If the graffiti declined, it means that A will be smaller than B, therefore d should be negative.
Therefore we can set:
H₀ : μd ≥ 0
H₁ : μd < 0
The equal sign would mean that the number of graffiti incidents remained constant, therefore it is part of the null hypothesis.
Therefore the correct answer is B) H₀: μd ≥ 0 versus <span>H₁</span>: μd < 0
We define the null hypothesis H₀ as the statement that is believed true until we prove it wrong with the test.
We define the alternative hypothesis H₁ as the statement we want to conclude with our test.
The difference in graffiti before (B) and after (A) will be:
d = A - B.
If the graffiti declined, it means that A will be smaller than B, therefore d should be negative.
Therefore we can set:
H₀ : μd ≥ 0
H₁ : μd < 0
The equal sign would mean that the number of graffiti incidents remained constant, therefore it is part of the null hypothesis.
Therefore the correct answer is B) H₀: μd ≥ 0 versus <span>H₁</span>: μd < 0