Question

A city wants to know if a new advertising campaign to make citizens aware of the dangers of driving after drinking has been effective. They count the number of drivers who have been stopped with more alcohol in their systems than the law allows for each day of the week in the week before and the week a month after the campaign starts.Here are the results:Before: (Monday-Sunday) 5,4,2,4,6,14,6After: (Monday-Sunday):2,0,2,1,8,7,7A) are the data paired? ExplainB) Compute the mean difference.C) Compute the standard deviation of the differencesD) Compute the standard error of the mean difference.E) Find the value of the t-statisticF) How many degrees of freedom does the t-statistic have?G) Is the alternative one or two sided? explainH) What is the p-value associated with this t-statistic?(Assume that the other assumptions and conditions for interference are met.) I)At a=0.05, what do you conclude?

Answer 1

a) yes data is paired

(b) the mean difference is = 7

c) the standard deviation = 3.1623

d) standard error = 1.195

e) the value of the t-statistic = 1.674

f) degrees of freedom does the t-statistic have = 6

g) Is the alternative one or two sided? = Since the researcher wants to know that if campaign is really effective or not so two tailed hypothesis will be used.

h) the p-value associated with this t-statistic = 0.1452

i) what do you conclude? = Since P-value is greater than ∝ = 0.05, so we fail to reject the null hypothesis. That is on the basis of sample evidence we can conclude that campaign is not effective.

Explanation: