Homework SourseI need help with these intro to statistics questions 1 Is th
I need help with these intro to statistics questions:
1) Is the mean height for all adult American males between the ages of 18 and 21 now over 6 feet? If the population of all adult American males between the ages of 18 and 21 has mean height of mu (where mu stands for population mean) feet and known standard deviation 0.2 feet, to answer this question one would test which of the following null and alternative hypotheses?
a) H0: mu = 6 vs. Ha: mu > 6 (where mu stands for population mean)
H0: mu = 6 vs. Ha: mu < 6 (where mu stands for population mean)
H0: mu = 6 vs. Ha: mu =/= 6 (where mu stands for population mean)
H0: mu = 6 vs. Ha: mu = 6 +/- sample mean (where mu stands for population mean)
2)Suppose that the batting average for all major league baseball players after each team completes 100 games through the season is 0.250 and the population standard deviation is 0.35. The null hypothesis is that the American League batters average the same as all other major league players. A sample of 49 players is taken from the American League reveals a mean batting average of 0.265. What is the value of the test statistic, z?
a) .43 b)1.0 c)0.3 d) 5.3
3)The proportion of defective computers built by Byte Computer Corporation is 0.15. In an attempt to lower the defective rate, the owner ordered some changes made in the assembly process. After the changes were put into effect, a simple random sample of 42 computers was tested revealing a total of 4 defective computers. Perform the appropriate test of hypothesis to determine whether the proportion of defective computer has been lowered. What is the value of the test statistic?
a) 0.9982 b)-0.9982 c)6.4693 d) -6.4693
| a) H0: mu = 6 vs. Ha: mu > 6 (where mu stands for population mean) | ||
| b) | H0: mu = 6 vs. Ha: mu < 6 (where mu stands for population mean) | |
| c) | H0: mu = 6 vs. Ha: mu =/= 6 (where mu stands for population mean) | |
| d) | H0: mu = 6 vs. Ha: mu = 6 +/- sample mean (where mu stands for population mean) |
Solution
(1)a) H0: mu = 6 vs. Ha: mu > 6 (where mu stands for population mean)
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(2) The test statistic is
Z=(xbar-mu)/(s/vn)
=(0.265-0.25)/(0.35/sqrt(100)
=0.43
Answer: a) .43
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(3) The test statistic is
Z=(phat-p)/sqrt(p*(1-p)/n)
=(4/42-0.15)/sqrt(0.15*(1-0.15)/42)
=-0.99
Answer: b)-0.9982
