1. An airline executive wishes to know if her airline is on schedule. She collects data on the
deviations from actual takeoff time. From a random sample of 35 takeoff deviations she finds the
mean to be 4.59 minutes (positive deviations being late) with a standard deviation of 16.32
minutes.
a. Is there sufficient evidence to conclude that the mean airline takeoff deviation is not zero at
the 0.05 level of significance?
b. Suppose the executive took a sample of 100 takeoff deviations and found the same sample
mean and standard deviation. What would her conclusion be then?
2. A government contractor is required to produce a part that has a mean service life greater than
2000 hours.
a. What would the hypotheses be if the government were trying to prove that the mean service
life was actually less than 2000 hours?
b. What would the hypotheses be if the contractor needed to prove that it was meeting the
requirement?
3. A machining process is established to produce metal wafers 2 inch thick. We wish to conduct a
test to see if the process mean is set correctly. Eighteen wafers are sampled and their thickness are
measured. The results are listed below:
2.005 2.003 2.001 2.001 2.005 2.006
1.999 1.998 2.007 1.997 2.004 2.003
2.008 2.002 2.000 2.005 2.005 2.004
c. What assumptions do we need to make in order to conduct this test?
d. Test at the 0.05 level of significance to see if the process mean is set correctly.
4. (Assume equal variances) Two water treatment reservoirs were examined to determine if there
was a difference in productivity. Differences in productivity are measured by the presence of four
types of microorganisms. After four samples were taken at each reservoir, the following sample
statistics were calculated. Assume data are normally distributed.
There's a quick view of it.. If you think you can get it done shoot me a PM. I will send a cleaner version so you can get a better look at it.
Getting FG via mtgo tix once I find someone who will help me out. Also will pay first
This post was edited by Si7c on Apr 10 2014 07:15pm