Standard Error2.974195Standard Error2.188452
Standard Deviation11.89678Standard Deviation8.753809
Sample Variance141.5333Sample Variance76.62917
Confidence Level(99.0%)8.764138Confidence Level(99.0%)6.44877
b. 99% confidence interval estimate for mean age of newly hired employees;
37.75 ¡V 8.76 = 28.99
37.75 + 8.76 = 46.51
Decision Rule: Reject Ho if t > t-critical
Do not reject Ho if t < t-critical
t-critical = t0.01,15 =2.602
0.771 < 2.602
Therefore, at a 99% Confidence Level the Null Hypothesis can not be rejected and we can not state that Riverside¡¦s mean duration of employment weeks is any greater than the mean duration of employment weeks within the rest of California.
d. Is there a relationship between the age of a newly employed individual and the number of weeks of employment?
By using a scatter plot and plotting the number of weeks employed in respect to the ages of the workers, you can see that the points are distributed along a straight line. The number of weeks employed increase positively as the age of the worker increases. Therefore it is safe to say that there is a positive correlation between the ages of newly employed workers and the number of weeks they are employed.
Textbook Exercise 7.6, The Trash Bag Case
Text Problem 7.6:
std dev. =1.6438
95% =0.509408783m =50.06559122
99% =0.669478969m =49.90552103
b.Yes, we can be 95% confident that the trash...