Are the underlined words (comparative adjectives) chosen correctly?

Hi,

"The one-way analysis of variance showed that there were significant differences in reaction time, transverse deviation, and VOSO and MCH scores among young, middle-aged and elderly groups (P-value = 0/000) and the longest reaction time (963 ms), the most vehicle transverse deviation (0.69 m), and the highest mental workload were related to the elderly group."

Can I replace "highest" with "greatest"?

Thanks!