Question 1010417
1.A 95% confidence interval for the mean of a normal population is found to be 17.6 < µ < 23.6. What is the margin of error?
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Every CI is 2*ME wide.
In your case:: 2*ME = (23.6-14.6) = 9
So ME = 4.5
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2.A 95% confidence interval for the mean of a normal population is found to be 13.2 < µ < 22.4. What is the margin of error?
2*ME = (22.4-13.2) = 9.2
ME = 4.6
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3.One hundred people are selected at random and tested for colorblindness to determine whether gender and colorblindness are independent. 
The critical value of X2 for a 2 x 2 table using a 0.05 significance level is 3.841. If the value of the X2 statistic is 4.613, state your conclusion about the relationship between gender and colorblindness.
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Since the test stat is greater than the critical value 
we reject Ho.  Therefore the factors are related.
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4.A golfer wished to find a ball that would travel more than 160 yards when hit with his 7-iron with a club speed of 90 miles per hour. He had a golf equipment lab test a low compression ball by having a robot swing his club 8 times at the required speed. 
Data from this test resulted in a sample mean of 163.2 yards with a sample standard deviation of 5.8 yards. Assuming normality, carry out a hypothesis test at the 0.05 significance level to determine whether the ball meets the golfer’s requirements.
Test Statistic:: 
(t(163.2) = (163.2-160)/(5.8/sqrt(8)) = 1.56
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Use the partial t-table below to solve this problem. 
Area in one tail
0.025	0.05
Area in two tails
Degrees of
Freedom
n - 1	0.05	0.10
6	2.447	1.943
7	2.365	1.895
8	2.306	1.860
9	2.262	1.833
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Ho: u <= 160
Ha: u > 160 (claim)
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Using n-1 = 7 with critical values 2.365 and 1.895
we fail to reject Ho that u <= 160
A.
Do not reject the null hypothesis. The data do not provide sufficient
evidence that the average distance is greater than 160 yards. 
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5.Which of the following statements is true? 
A. The t distribution cannot be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population. 
B. The t distribution can be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population. 
C. The p distribution can be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population. 
D. The p distribution can be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population. 
Ans: I'll leave this one to you.  Check your textbook.
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Cheers,
Stan H.
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