(a). For the 10 yd distance, the value of time in each trial is,
1.89 s, 1.83 s, and 1.72 s
The average value of time for 10 yd distance is,
![\begin{gathered} t_1=(1.89+1.83+1.72)/(3) \\ t_1=1.81\text{ s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/d9cak6azq74stg6zps2ut3krbhqsdjqz51.png)
Thus, the average time for 10 yd is 1.81 seconds.
For 20 yd distance, the value of time in each trial is,
3.12 s, 3.28 s, and 3.47 s
The average value of time for 20 yd is,
![\begin{gathered} t_2=(3.12+3.28+3.47)/(3) \\ t_2=3.29\text{ s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/qjqfdl2w0ftwk7apspnqegrhee27ksl8v7.png)
Thus, the average time for 20 yd is 3.29 seconds.
For 30 yd distance, the value of time in each trial is,
5.55 s, 5.14 s, and 4.44 s
The average value of time for 30 yd is,
![\begin{gathered} t_3=(5.55+5.14+4.44)/(3) \\ t_3=5.04_{}\text{ s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/o4oqafr1iwctsq5cct368k4xxz77otez0r.png)
Thus, the average time for 30 yd is 5.04 seconds.
For 40 yd distance, the value of time for each trial is,
7.16 s, 7.24 s, and 6.78 s
The average value of time for 40 yd is,
![\begin{gathered} t_4=(7.16+7.24+6.78)/(3) \\ t_4=7.06\text{ s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/6ojrf933chvrf8wspjde8d9491e6yi68k6.png)
Thus, the average value of time for 40 yd is 7.06 seconds.