Statistics - Confidence Interval and Hypothesis Testing

2. A sample of 81 observations is taken from a normal population. The sample mean is 40, and the sample standard deviation of 5. Determine the 95 percent confidence interval for the population mean.
3. Merrill Lynch Securities and Health Care Retirement, Inc, are two large employers in down Toledo, OH. They are considering jointly offering child care for their employees. ...
4. The Greater Pittsburgh Area Chamber of Commerce wants to estimate the mean time workers who are employed in the downtown area spend getting to work. A sample of 15 ...
5. The manufacturer of the X-15 steel-belted radial truck tire claims that the mean mileage the tire can be driven before the tread wears out is 60,000 miles. ...
6. The MacBurger restaurant chain claims that the waiting time of customers for service is normally distributed, with a mean of 3 minutes and a standard deviation of 1 minute ...

1. What are the null and alternate hypotheses for this test? Why?
2. What is the critical value for this hypothesis test using a 5% significance level?
3. Calculate the test statistic and the p-value using a 5% significance level.
4. State the decision for this test.
5. Determine the confidenceinterval level that would be a

Need help setting up, understanding and solving this problem:
At Western University the historical mean of scholarship examination scores for freshman applications is 900. A historical population standard deviation σ = 180 is assumed known. Each year, the assistant dean uses a sample of applications to determine whether

Assume that in a hypothesis test with null hypothesis = 13.0 at 0.05, that a value of 11.0 for the sample mean results in the null hypothesis not being rejected. That corresponds to a confidenceinterval result of
A. The 95% confidenceinterval for the mean does not contain the value 13.0
B. The 95% confidenceinterval for

1. A sample of 25 MBA students taking OTM course in the Spring of 2013 shows an average income of $85,000 with the sample standard deviation of $5,000. Find the 95% confidenceinterval of the population mean income of MBA students.
2. According to a study, the mean (μ) price of a gallon of the regular gasoline in the United

Consider the following HypothesisTesting:
H0: δ1² = δ2²
Ha: δ1² ≠ δ2²
The sample size for sample 1 is 25, and for sample 2 are 21. The variance for sample 1 is 4.0 and for sample 2 is 8.2
a) at the confidence level of 0.98, what is your conclusion of this test?
b) What is the confidence

What is the relationship between a confidenceintervaland a single sample, two-tailed hypothesis test?
How are they the same? How are they different?
Review the definition of a single sample, two tailed test. Now review the structure of a confidenceinterval.
What are the assumptions and requirements for the use

Consider that 10 observations were selected from a normal population whose variance is 64. Observations are: 58, 62, 45, 50, 59, 65, 39, 40, 41 and 52. Check to 5% (.05) level of significance if there is sufficient evidence to conclude that the average population is 45.
Calculate the sample average.
Calculate the standard

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The Osborne manufacture makes a soft drink dispensing machine that allows customers to get soft drinks from the machine in a cup with ice. When the machine is running properly, the average number of fluid ounces in the cup should be 14. Periodically the machines need