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Testing of hypothesis problems

2 problems that I need help with.
# 4) A legal researcher is studying the age distribution of juries by comparing
them with the overall age distribution of available jurors. The researcher
claims that the jury distribution is different from the overall distribution; that
is, there is a noticeable age bias in jury selection in this area.The table shows
the number of jurors at a county court in one year and the percent of persons
residing in that county, by age. Use the population distribution to find the
expected juror frequencies.Test the researcher's claim at a = 0.01

21-29 30-39 40-49 50-59 60 and above
Jury 45 128 244 224 359
population 20.50% 21.70% 18.10% 17.30% 22.40%

#16) A steel pipe fittings company claims that the yield strength of its non tempered
couplings is more variable than that of its tempered couplings.
A random sample of nine tempered couplings has a standard deviation of
13.1 megapascals, and a similar sample of nine nontempered couplings has
a standard deviation of 25.4 megapascals. From past data, it is known that
the company's production process results in normally distributed yield
strengths.Test the company's claim at a = 0.05.


Solution Summary

The solution provides step by step method for the calculation of test statistic . Formula for the calculation and Interpretations of the results are also included.