Question

twenty - six football players ran a lap after practice. their lap times in seconds are shown in the following stem - and - leaf plot. 6|1 2 3 3 6|6 7 7|1 1 2 7|5 6 8 8 9 9 8|1 2 2 2 3 8|7 7 8 9 9|2 4 leaf unit = 1.0 s what is the median lap time? sec (do not round)

Explanation:

Step1: Count the number of data - points

There are $n = 26$ data - points.

Step2: Determine the position of the median

Since $n = 26$ (an even number), the median is the average of the values at positions $\frac{n}{2}$ and $\frac{n}{2}+1$. Here, $\frac{n}{2}=\frac{26}{2}=13$ and $\frac{n}{2}+1 = 14$.

Step3: List out the data in ascending order

The data set is: $61,62,63,63,66,67,71,71,72,75,76,78,78,79,79,81,82,82,82,83,87,87,88,89,92,94$.

Step4: Find the 13th and 14th ordered data - points

The 13th value is $78$ and the 14th value is $79$.

Step5: Calculate the median

Median=$\frac{78 + 79}{2}=78.5$

Answer:

$78.5$