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Two different water supplies 1 and 2 are being investigated for concentrations of dangerous chemicals.  The existing claim is that both supplies contain the same amount.  We want to conduct a hypothesis test to see if supply 2 has larger amounts of these chemicals at 5% significance level.  Assume both populations are independent and normal.  To this end, we collect a simple random sample from each process.

A group of 15 students has performed an experiment, they measured the coefficient of thermal expansion for aluminum. The results are as follows:  22.0 25.9 25.6 23.1 22.7 25.6 24.9 21.9 26.1 24.3 23.5 20.7 21.4 23.5 20.4   Is there strong evidence to conclude that the standard deviation in this experiment exceeds 3 at significance level of 0.05? Find the P-value for this test. 

An article in the ASCE Journal of Energy Engineering [“Overview of Reservoir Release Improvements at 20 TVA Dams” (Vol. 125, April 1999, pp. 1–17)] presents data on dissolved oxygen concentrations in streams below 20 dams in the Tennessee Valley Authority system. The observations are (in milligrams per liter): 5.0, 3.4, 3.9, 1.3, 0.2, 0.9, 2.7, 3.7, 3.8, 4.1, 1.0, 1.0, 0.8, 0.4, 3.8, 4.5, 5.3, 6.1, 6.9, and 6.5. Test the hypothesis versus . Use . Is it possible to reject hypothesis at the 0.01 level of significance? Find the P-value.

In a random sample of 500 handwritten zip code digits, 464 were read correctly by an optical character recognition (OCR) system operated by the U.S. Postal Service (USPS). USPS would like to know whether the rate is at least 90% correct. Do the data provide evidence that the rate is at least 90% at significance level of 0.05? Find the p-value of the test.

The appendix is an extension of the: 

During the eye exam of a 50-year-old hypertensive patient who is complaining of onset of a severe headache, you find that the borders of the disc margins on both eyes are blurred. What is the name of this clinical finding?

During a sports physical on a 14-year-old athlete, you notice a split S2 component of the heart during inspiration that disappears with expiration. The heart rate is regular and no murmurs are auscultated. Which of the following is considered correct?  

Baby Joe is 6 months old. He has abdominal distention and is vomiting and inconsolable. A sausage-shaped mass is palpable in his right upper quadrant. Joe’s lower quadrant feels empty, and a positive Dance sign is noted in his record. Which one of the following conditions is consistent with Baby Joe’s symptoms? 

Peristalsis of intestinal contents is under the control of: 

Which ear structure is responsible for equalizing atmospheric pressure when swallowing, sneezing, and yawning?