Dear students,
Although this form is typed, you must hand in your homework in your own handwriting. That
is, photocopied or typed homework WILL NOT be acceptable. And graders often deduct
points for:
1. late submissions (1 point every day after the due date)
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The following identification fields are necessary to ensure your hard work is accurately
recorded by your grader. Please help him with this by providing him the following
information;
1) Course number: STAT 319
2) Instructor name: Dr. Mohammad H. Omar
3) Homework number: e.g. 1 (chapter 1)
4) Section Number (or class time): 01 (8am) or 03(9am)
5) Student ID: e.g 2005123456
6) Student Name: e.g. Mr Mohammad Yahya Abdulla
Course number: STAT 319
Instructor name: Dr. Mohammad H. Omar
Homework number: chapter 10 Section # (or class time): 03 or 9:00 class
Student ID: ____________ Student Name:__________________
STAT 319, TERM 073
Chapter 10: Hypothesis Testing
Q1. The article "Ozone for removal of acute toxicity from logyard run-off" (M. Zenaitis and S Duff, 2202,
Ozone Science and Engineering, 83-90) presents chemical analyses of runoff water from sawmills in
British Columbia. Included were measurements of pH for six water specimens: 5.9, 5.0, 6.5, 5.6, 5.9, and
6.5. Experience says that these type of pH contents follow normal distribution.
1.
a) Test the hypothesis that true pH content is more than 5.5.
b) Test the hypothesis that true pH content is less than 5.5.
c) Test the hypothesis that true pH content is 5.5.
d) Would you modify the method of testing if sample size were large? (T)
Q2. The pH content of runoff water from sawmills in British Columbia is considered. Six water specimens
produce a mean of 5.5. Experience says that these type of pH contents follow normal distribution with
standard deviation 0.81.
a) Test the claim that true pH content is more than 5.65.
b) Would you modify the method of estimation if sample size were large? RT)
Q3. The pH content of runoff water from sawmills in British Columbia is considered. Thirty water
specimens produce a mean of 5.5. Experience says that these type of pH contents follow normal
distribution with standard deviation 0.81.
a) Test the claim that true pH content is different from 5.65.
b) Would you modify the method of estimation if sample size were large? (CLT)
Q4. The pH content of runoff water from sawmills in British Columbia is considered. Thirty water
specimens produce a mean of 5.5 and standard deviation 0.81. Test the claim that true pH content is less
than 5.65. (ST)
Q5. Concentrations of atmospheric pollutants such as carbon monoxide (CO) can be measured with a
spectrophotometer. In a calibration test, 40 measurements were taken of a laboratory gas sample that is
known to have a CO concentration of 80 parts per million (ppm). A measurement is considered to be
satisfactory if it is within 5 ppm of the true concentration. Of the 40 measurements, 36 were satisfactory.
Test the claim that the proportion of satisfactory measurements is more than 0.80.
2