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95% confidence interval for mean differences

What would be the 95% confidence interval for this difference?

95% CI = mean difference +/- 2(standard error of the difference)

t = 5.185
df = 13201
mean dif = -.16
Std. Error Dif = .031
95% CI (lower -.221)
(upper -.100)

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Let's take a closer look. First, this response points out how the computer print-out gives you the confidence interval and then we manually calculate the interval to see how the computer used this formulas to get the upper and lower levels of the 95% confident interval.

RESPONSE:

95% CI = mean difference +/- 2(standard error of the difference)

t = 5.185
df = 13201
mean dif = -.16
Std. Error Dif = .031 ...

Solution Summary

This solution addresses the question: What would be the 95% confidence interval for this difference?

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