# Statistics

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Juan makes a measurement in a chemistry laboratory and records the result in his lab report. The standard deviation of students' lab measurements is 10 milligrams. Juan repeats the measurement 3 times and records the mean (x-bar) of his 3 measurements.

a) What is the standard deviation of Juan's mean result? (that is, if Juan kept on making 3 measurements and averaging them, what would be the standard deviation of all his means?)

==> I don't quite understand this concept...can someone please explain this to me? Thanks! :)

• Statistics -

Standard deviation of a distribution of means = standard error of the mean = SEm

SEm = SD/√(n-1)

• Statistics -

7.071?

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