Q238 · Practice questionTechnology-activeComplex unfamiliar6 marks
QUESTION 238 (6 marks)
Two independent random samples have means and , standard deviations and , and sample sizes and respectively.
a)[3 marks]
Estimate the standard error of the difference in sample means.
b)[2 marks]
Form an approximate confidence interval for using .
c)[1 mark]
Interpret whether zero is plausible under this interval.
WORKED SOLUTION
6 marksPractice marking scheme
ANSWER
Zero is not in the interval, so under the model the data provide evidence of non-zero difference in population means.
Worked solution
Part (a): .
Part (b): Difference. . .
Part (c): Zero is not in the interval, so under the model the data provide evidence of non-zero difference in population means.
Part (a): completes the requested reasoning and obtains a correct result.
Part (b): completes the requested reasoning and obtains a correct result.
Part (c): completes the requested reasoning and obtains a correct result.
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