UMUC STAT 200 STAT/200 STAT200 Quiz 3 with Answers (Updated 2017)


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If the P-value of a hypothesis test comparing two means was 0.25, what can you conclude?

2. (4 points) Imagine a researcher wanted to test the effect of the new drug on reducing blood pressure. In this study, there were 50 participants. The researcher measured the participants’ blood pressure before and after the drug intake. If we want to comparethe mean blood pressure from the two time periods with a two-tailed t test, how many degrees of freedom are there?


3. (4 points) When sample size increases, 


4. (4 points) α=0.05 for a two-tailed test. Assume that the data has a normal distribution and the number of observations is greater than fifty. Find the critical z value used to test a null hypothesis.


5. (4 points) In a sample of 47 adults selected randomly from one town, it is found that 9 of them have been exposed to a particular strain of the flu. Find the P-value for a test of the claim that the proportion of all adults in the town that have been exposed to this strain of flu is 8%.


6. (4 points) For a simple random sample, the size is n=17, σ is not known, and the original population is normally distributed. Determine whether the give conditions justify testing a claim about a population mean µ.


8. (4 points) The duration of telephone calls directed by a local telephone company: σ=4.2 minutes, n=400, 97% confidence. Use the confidence level and sample data to find the margin of error E.


9. (15 points) Below are the statistics for electricity usages of two neighborhoods. Perform a hypothesis test to settle the dispute that neighborhood 1 uses less energy than neighborhood 2.


10. (15 points) It is commonly accepted that the mean temperature of human is 98.6oF. Yours truly has nothing better to do but measured the temperatures of 26 colleagues 1 to 4 times daily to get a total of 123 measurements. The collected data yielded a sample mean of 98.4oF and a sample standard deviation of 0.7oF. Is the mean temperature of his colleagues less than 98.6oF at the 0.01 significance level? Justify your answer with the proper statistics.


11. The recommended daily allowance (RDA) of cobalamine (Vitamin B12) for growing teens is 2.4 µg (micrograms). It is generally believed that growing teens are getting less than the RDA of 2.4 µg of cobalamine daily.