Two random samples are selected from two independent populations. A summary of t
ID: 3319417 • Letter: T
Question
Two random samples are selected from two independent populations. A summary of the samples sizes, sample means, and sample standard deviations is given below: n1=49,n2=38,x¯1=55,x¯2=74.2,s1=5.5s2=10.9 Find a 92.5% confidence interval for the difference 12 of the means, assuming equal population standard deviations. (HINT: See Chapter 22, Section 7 in the text.) Confidence Interval = What is the critical value used in your confidence interval? What is the standard error of the difference in sample means that is used in your confidence interval?
Explanation / Answer
The statistical software output for this problem is:
Two sample T summary confidence interval:
1 : Mean of Population 1
2 : Mean of Population 2
1 - 2 : Difference between two means
(with pooled variances)
92.5% confidence interval results:
Hence,
Confidence interval = (-22.2319, -15.7681)
Critical value = 1.803
Standard error = 1.793
Difference Sample Diff. Std. Err. DF L. Limit U. Limit 1 - 2 -19 1.7929282 85 -22.23188 -15.76812Related Questions
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