Question

In a study of driving practices in Strathcona County, Alberta, Canada, it was found that 48% of drivers did not stop at stop sign intersections on county roads. Assume that a follow-up study two months later found that 360 of 800 drivers did not stop at stop sign intersections on county roads. Use a 5% significance level to see whether the proportion of drivers who did not stop has changed.

1.   Copy and paste the Minitab output for exercise into the document underneath the problem.   You are not also required to do these by hand, unless you want to.  

2. Write the rejection rule word for word as written here, "Reject Ho if the p-value is less than or equal to alpha."

3.   Write the actual p-value and alpha, then either "Reject Ho" or "Do not reject Ho." As an example: 0.0021 ≤ 0.05. True. Reject Ho.

4.    Write an English sentence stating the conclusion, claim, and significance level. As an example: If the claim is "Can we conclude that male business executives are taller, on the average, than the general male population at the  α  = 0.05 level?", and if we found our conclusion to be do not reject Ho, the sentence would be, "There is not enough evidence to conclude that  male business executives are taller, on the average, than the general male population at the  α  = 0.05 level."

Answer 1

1)

2)

Rejection rule:

Z critical = 1.96 (Use Z table)(Two tailed)

If |Z| stat > Z critical, H0 rejected

If P value < 0.05, Reject H0

3)

P value = 0.089

P value > 0.05, Do not reject H0

4)

Therefore, there is not enough evidence to conclude that the proportion of drivers who did not stop has changed at 5% significance level