Question

In a student survey, forty part-time students were asked how many courses they were taking this term. The (incomplete) results are shown below: Please round your answers to 4 decimal places.

# of Courses Frequency Relative Frequency Cumulative Frequency

1 11 ? 11

2 ? 0.425 28

3 12 0.3 ?

What percent of students take exactly two courses?

%

Answer 1

42.5%

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%