Question

What is the first quartile, Q1, of the data set?

{36, 45, 79, 80, 82, 85, 90}



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Q1 = ?

Answer 1

45 I just took the quiz and got it right

Answer 2

Step 1) Sort the data values. Since the data is already sorted for us, we can skip to step 2

Step 2) Identify the median of the given data set. The median is the middle most value. In this case, its the value 80 which is in the 4th slot. There are 3 values to the left of the median, and there are 3 values to the right of the median.

Step 3) Break the given data set into two halves such that the lower half data set is L = {36, 45, 79}
Notice how everything in set L is the set of values smaller than the median found back in step 2

Step 4) Find the median of set L. The median of this sub-set is 45
The median of the lower half of data values is the first quartile Q1.
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Final Answer: 45