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10/01/10 PROP: Hypo&CI&pVal&STS Place on each page: [1] Your CLASS ID at the top right and your course (like “385”), then your name.
Hand in BEFORE YOU SIT DOWN  EVEN IF I'M LECTURING . After you sit down or after class it will
not count. If more than one page, they must be stapled for credit. No credit if torn edges.
A. Airline passengers now tend to carry more baggage online rather than checking it. Test at α = 0.10
whether the population mean of carryon baggage is at least 12 pounds. A sample of 16 passengers gave a
mean of 9 pounds and a standard deviation of 8. Use the Z table.
Do the 5 steps as indicated in class. SHOW RAW FORMULAS without numbers, and show work
carefully. Draw the graph with 2 axes and LABEL!
(5 steps: 1. State Hypotheses; 2. Compute CV(s); 3. State Decision rule: REJECT Ho IF ___ ;
4. State decision: SINCE___; 5. State conclusion. ) _ B. Notice that the Xsample = 9. Show raw formula and show work in computing the tail area for the sample
_
result. Thus, what is the tail area for 9? On your graph above draw the line for Xsample = 9 and label
the tail area for the sample result. (This tail area for the sample result has a name: it is called the pvalue  and the dash is required so it is NOT pvalue.) C. Define α as the probability of something: D. If we did this process many times (set α=0.10, obtain a sample from the population, and conduct the
hypothesis test), sometimes we’d be led by the sample to reject Ho. Of all these times that we’d be led to
reject Ho, what percentage of those times will we make an error when rejecting the null hypothesis? E. A certain prescription drug requires a concentration of 200 ppm (parts per million) to be effective. If the
concentration is too low, this could be dangerous for the patient.
Test at α = 0.025 whether the population average concentration is more than 200 ppm. A sample of 64
gave a mean of 210 ppm and a standard deviation of 32.
Do the 5 steps as indicated in class. SHOW RAW FORMULAS without numbers, and show work
carefully. Draw the graph with 2 axes and LABEL!
(5 steps: 1. State Hypotheses; 2. Compute CV(s); 3. State Decision rule: REJECT Ho IF ___ ;
4. State decision: SINCE___; 5. State conclusion. _ F. Notice that the Xsample = 210. Show raw formula and show work in computing the tail area _ the
for
sample result. Thus, what is the tail area for 210? On your graph above draw the line for Xsample = 210
and label the tail area for the sample result. (This tail area for the sample result has a name: it is called
the G. pvalue and the dash is required so it is NOT pvalue.) If we did this process many times (set α=0. 025, obtain a sample from the population, and conduct the
hypothesis test), sometimes we’d be led by the sample to reject Ho. Of all these times that we’d be led to
reject Ho, what percentage of those times will we make an error when rejecting the null hypothesis? ...
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 Winter '11
 kim

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