The Department of Economic and Community Development (DECD) reported that in 2009 the average number of new jobs created per county was 450. The department also provided the following information regarding a sample of 5 counties in 2010.
County New Jobs Created In 2010
Bradley 410
Rhea 480
Marion 407
Grundy 428
Sequatchie 400
a. Compute the sample average and the standard deviation for 2010. (round to two decimal place)
b. We want to determine whether there has been a significant decrease in the average number of jobs created. Provide the null and the alternative hypotheses.
c. Compute the test statistic.
d. Compute the critical value; and at 95% confidence, test the hypotheses.
Answers
The Department of Economic and Community Development (DECD) reported that in 2009 the average number of new jobs created per county was 450. The department also provided the following information regarding a sample of 5 counties in 2010.
County New Jobs Created In 2010
Bradley 410
Rhea 480
Marion 407
Grundy 428
Sequatchie 400
a. Compute the sample average and the standard deviation for 2010. (round to two decimal place)
b. We want to determine whether there has been a significant decrease in the average number of jobs created. Provide the null and the alternative hypotheses.
c. Compute the test statistic.
d. Compute the critical value; and at 95% confidence, test the hypotheses.
Explanation:
xbar = 425
s = 32.435
n = 5
a. test statistic: t = (425 - 450) ÷(32.435/√(5))
= -1.724
p-value = 0.08
critical value = 2.132
Do not reject