Using their concepts concept, we have that:
a) The mean of the data-set is of 81.6.
b) The median of the data-set is of 80.
What is the mean?
The mean of a data-set is given by the sum of all observations in the data-set divided by the number of observations.
In this problem, there are 2 + 8 + 6 + 3 + 9 = 28 observations, hence the mean is:
M = (70 x 2 + 75 x 8 + 80 x 6 + 85 x 3 + 90 x 9)/28 = 81.6.
What is the median?
The median of a data-set is the 50th percentile, the value that separates the median in two halfs.
This data-set has an even number of elements, hence the median is the mean of the 14th and 15th elements, as 28/2 = 14. Both elements are 80, hence the median is of 80.
More can be learned about the mean and the median of a data-set https://brainly.com/question/13202035
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