During the winter of 2008-2009, the average utility bill for residents of a cert
ID: 3316605 • Letter: D
Question
During the winter of 2008-2009, the average utility bill for residents of a certain state was $173 per month. A random sample of 20 customers was selected during the winter of 2009-2010, and the average bil l was found to be $164 28 with a sample standard deviation of 520.86. Complete parts a and b below a) Using 0.05, does this sample provide enough evidence to conclude that the average utility bill in this state was lower in the winter of 2009-2010 than t was in the winder of 2008-2009? Determine the hypotheses. 0 A. Ho : 2 1 73 and H1 : : 173 O B. Ho : s 173 and H1 : >173 Determine the critical value(s). The critcal value(s) is(are) Round to three decimal places as needed. Use a comma to separate answers as needed.) Determine the test statistic, t (Round to two decimal places as needed) What conclusion should be drawn O A. Reject Ho. There is not sumicient evidence to conclude that the average utiity bill in this state was lower in the winter of 2009-2010 than it was in the winter or 2008-2009. B. Reject Ho T here is suficient evidence to conclude that the average utlity bill in this state was lower in the winter of 2009-2010 than it was n the winter of 2008-2009 OC. Do not reject Ho. There is not sutficient evidence to conclude that the average utility bill in this state was lower in the winter ot 2009-2010 than it was in the winter of 2008-2009 O D Do not reject Ho There is sufficient evidence to conclude that the average utility bil in this state was lower in the winter of 2009-2010 than it was in the winter of 2008-2009.Explanation / Answer
The statistical software output for this problem is:
One sample T summary hypothesis test:
: Mean of population
H0 : = 173
HA : < 173
Hypothesis test results:
Hence,
Hypotheses: Option D is correct.
Critical value = -1.729
t = -1.87
Option C is correct.
b) Option C is correct.
c) p = 0.039
Mean Sample Mean Std. Err. DF T-Stat P-value 164.28 4.6622017 19 -1.8703609 0.0385Related Questions
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