Answer:
Mode: 13.9
Median: 13.1
LQ: 11.7
UQ: 13.9
IQR: 2.2
Explanation:
To make a stem and leaf diagram for this, just remember, for figures with decimals, the stem will be the whole numbers and the leaves would be the decimals.
100m race TIME IN SECONDS
STEM LEAVES
10 | 2, 6
11 | 4, 7
12 | 4, 8, 9
13 | 1, 3, 6, 9, 9
14 | 2
15 | 4
17 | 3
To find the mode, all you need to do is find the number that occurs the most times. In this case, we have 13.9 as our mode because it occurs twice, while all other values occur once.
As for the median, all you need to do is find the value that is found in the middle of all the data. Since we have 15 data points, you just find the 8th value. You can count from the bottom or the top. You will fin that 13.1 is the median.
Next is the lower and upper quartiles. The lower and upper quartiles can be found by looking for the center value or middle value of the data that fall in the lower side of the median (Lower quartile) and the middle value of the data that falls on the higher side of the median (Upper quartile).
Lower quartile:
We have 7 data points below the median. So the middle of 7 is the 4th data point. So look for the 4th data point. The lower quartile will then be 11.7.
Upper quartile:
We have 7 data points above the median, so we also get the 4th data point. The upper quartile is then 13.9.
Now to get the interquartile range, just get the difference between the upper and lower quartile:
13.9 - 11.7 = 2.2.