Answer:
+or-6
Step-by-step explanation:
This is a trick question. The answer would be the first choice since you're multiplying -6 by +or-6, meaning that it could still end up as a negative or a positive.
Answer:
d. 20
Step-by-step explanation:
Standard deviation is 4.5
Margin error for the problem is 2 hours
Probability 95%, that means that the siginficance level α is 1 – p
α = 1 – 0.95 = 0.05
margin of error (ME) can be defined as follows
ME = Z(α/2) * standard deviation/ √n
Where n is the sample size
Z(0.05/2) = Z(0.025)
Using a z table Z = 1.96
Now, replacing in the equation and find n
2 = 1.96 * 4.5/ √n
2 = 8.82/√n
√n = 8.82/2
√n = 4.41
n = 4.41^2
n = 19.44 ≈ 20
