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Twenty students scored the following marks in a history test: 5, 2, 5, 3, 1, 6, 2, 2, 3, 4, 2, 1, 2, 2, 4, 3, 2, 2, 2, 3. What is the mode of distribution. What is the median and mean

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Answers:

  • Mode = 2
  • Median = 2
  • Mean = 2.8

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Work Shown:

Original set = {5, 2, 5, 3, 1, 6, 2, 2, 3, 4, 2, 1, 2, 2, 4, 3, 2, 2, 2, 3}

Sorted set = {1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 5, 5, 6}

Do not toss out the duplicates.

The most occurring or most frequent value is 2, so this is the mode.

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To find the median, we divide the n = 20 item set into two parts

n/2 = 10

So we'll count to the 10th slot to get to the number "2", which is the second to last "2" in the sorted list shown above.

The number just after this is also "2" in the 11th slot. Average these two values to get (2+2)/2 = 4/2 = 2

The median is 2.

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To find the mean, we need to first add up all the data values.

1+1+2+2+2+2+2+2+2+2+2+3+3+3+3+4+4+5+5+6 = 56

Then divide this over n = 20 to get 56/20 = 2.8

The mean is 2.8

The mean being larger than the median tells us we have an outlier that is larger than the main cluster. Those outliers are 5 and 6.

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