$2.$ A large county school system tracks annual state$-$level evaluations of their middle schools shown below for AY$22-23.$ Not all schools were rated due to some exemptions.

Cumulative Cumulative Valid Cumulative

Rating Number Percent Frequency Percent Percent Valid Percent

A $20$

B $50$

C $30$

D F $10$

$15$

No rating $10$

a$)$ Complete the percent, cumulative frequency, cumulative percent, and valid percent columns AND the $$total$$ row above. $(1$ each cell$)$

b$)$ Of those rated this year, what percent got at least a $$B$$ grade? $(5)$

c$)$ How many schools got a $$C$$ or lower? $(5)$