Please explain why my teacher interpret each quantity financial index like this (teacher's explanation was shown in the red letter in above picture)

I don't understand why teacher use -1.78 as cut off in m-score

, and why teacher interpret another index like these please. help me cleary expain.

(and table below is another information of the data above, it's only the information that may help you to answer this question easier)

Thank you so much for your helping!

ABD Co.: Financial information					2018	2019	2020
Current ratio(times)					1.44	1.47	1.5
Quick ratio(times)					0.62	0.79	0.58
Cash ratio(times)					0.06	0.04	0.04
Cash flow from operating activity					19,943,652	17,675,432	17,943,657
Cash flow from investing activity					-14,777,065	-18,732,456	-16,234,567
Cash flow from financing activity					-9,422,372	-8,235,671	-8,342,009
Fixed assets turnover					6.77	6.24	6.09
Total assets turnover					1.76	1.88	1.61
Capital expenditure					7,798,285	8,237,301	7,832,019
Reinvestment cashflow coverage					2.56	2.15	2.29
Cash					(4,255,785)	(9,292,695)	(6,632,919)