Part 1: The lower quartile of a data is the value which divides the lower half of a data into two equal parts.
Given the data set: <span>25,8,10,35,5,45,30,20 Arranging the data set, we have: 5, 8, 10, 20, 25, 30, 35, 45
The lower half of the data set is: 5, 8, 10, 20 and half of the lower half of the data is given by (8 + 10) / 2 = 18 / 2 = 9.
Therefore, the </span><span>lower quartile of the data set is 9. (option c)
Part 2: The </span>box -and-whisker plots <span>are divided into sections using quartiles and extremes. In a box and whisker, the end point of the left whisker represents the minimum value while the right whisker represents the maximum number. The left edge of the box represent the lower quartile while the right edge of the box represent the upper quartile.
A line inside the box represent the median of the data set.
Part 3: </span><span>In constructing a box-and-whisker plot for the data set below, the left and right sides of the box is drawn at the lower and the upper quartile of the data set.
Arranging the dat set, we have: 1, 2, 3, 3, 4, 5, 6, 7, 8, 8, 9 The lower quartile of the data set is 3 while the upper quartile of the data is 8.
Therefore, the left side of the box is at 3 while the right side of the box is at 8. </span>
