Develop a 95% confidence interval for the difference in mean

Question

Question 1. Consider the following results for two samples randomly taken from two normal populations with equal variances.

		Sample I	Sample II
	Sample Size	28	35
	Sample Mean	48	44
	Population Standard Deviation	9	10

a.   Develop a 95% confidence interval for the difference between the two population means.

b.   Is there conclusive evidence that one population has a larger mean? Explain.

 

Question  2. As a general guideline, the research hypothesis should be stated as the 

		null hypothesis
		hypothesis the researcher wants to disprove
		alternative hypothesis
		tentative assumption

Question  3. As the degrees of freedom increase, the t distribution approaches the

		uniform distribution
		p distribution
		exponential distribution
		normal distribution

Question 4. Two approaches to drawing a conclusion in a hypothesis test are

		p-value and critical value
		Type I and Type II
		one-tailed and two-tailed
		null and alternative

Question 5. In hypothesis testing, the alternative hypothesis is

		the maximum probability of a Type I error
		All of the answers are correct
		the hypothesis tentatively assumed true in the hypothesis-testing procedure
		the hypothesis concluded to be true if the null hypothesis is rejected