2015 r 29 30 consider the data set 405 375 475 375 475 55 65...

Consider the data set (40.5, 3.75, 4.75, 3.75, 4.75, 5.5, 6.5). What change in the mean occurs when the outlier is removed? (a) decrease by approximately 6.5 (b) decrease by approximately 5.5 (c) decrease by approximately 5.1 (d) no change In which data set is the median and mean equivalent? (a) 2,4,6,7,8 (b) 10,13,18,20,29 (c) 12,18,20,24,25 (d) 50,60,65,75,85

Transcript

00:01 This probably gives us two questions regarding data sets, and the first one wants us to consider the given data set, and we want to answer what change in the mean occurs when the outlier is removed.

00:11 And before the outlier is removed, our mean or our average would be found from adding up all our values, which would give us 69 .5, and the dividing by the total number of observations, which is seven.

00:22 And that gives us, rounded to one decimal place, a mean of 9 .9.

00:27 So that's our average or our mean when we let the outlier be included.

00:31 Our outlier here would be the 40 .5 because that's well and away from all the other observations that we are seeing.

00:37 So if we got rid of that and then found our sum of our six observations, our sums total would be 29.

00:45 And then we would divide by six and not seven to find that average.

00:48 And that average comes out to round it to one place, 4 .8.

00:51 So it looks like the mean dropped from 9 .9 to 4 .8 when we got it.

00:57 Rid of that outlier and that means that our choice for what happens to the mean would be choice c it decreases by approximately 5 .1 because 9 .8 minus 4 or 9 .9 minus 4 .8 does give us 5 .1 so c is the right choice there.

01:12 For our second question we want to know which data set is the median and the mean equivalent and what's nice about these four choices is that they give us four data sets already in order from least to greatest and they're all data sets with observations that are of five observations...

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