Answer:
42.5%
Step-by-step explanation:
First we have to complete the table. We know that there are forty part time students so sum(f)=n=40. So, for two courses frequency is 40-11-12=17.
The relative frequency is the proportion of respective frequency and the sum of frequency. So, the missing relative frequency for 1st course is 11/40=0.275.
The missing relative frequency can also be computed as by subtracting given relative frequencies from 1 as sum of relative frequencies is 1. So, 1-0.425-0.3=0.275.
The cumulative frequency of respective class is the sum of frequency of previous classes and frequency of respective class. The missing cumulative frequency is 11+17+12 or 28+12= 40.
So, the complete table is
# of Courses Frequency Relative Frequency Cumulative Frequency
1 11 0.275 11
2 17 0.425 28
3 12 0.3 40
The percent of students takes exactly two courses=0.425*100=42.5%
