Mason conducted a survey of his class to determine if they prefer to use pens or pencils for their math homework. Out of the 30 students in his class, 12 of them are male. A total of 21 students said they prefer pencils, and 12 of those students are female. Fill in the missing joint and marginal frequencies in the table.

Pencils Pens Total
Male
% 10% 40%
Female
% 20%
%
Total 70%
% 100%

Step-by-step explanation:

-Total column

30 students in the class

12 male , so 30-12 = 18 female

-Pencils column

21 students prefer pencils

12 female that prefer pencils , 21-12 = 9 male that prefer pencils

-Total row

21 students prefer pencils

30 students total, 30-21 = 9 students prefer pens

-Pens column

12 students male -9 students male prefer pencil =3  students male prefer pens

18 students female -12 students female prefer pencil =6  students female prefer pens

-to calculate the % always find the equivalent fraction of

30 students/ 100% = number of students you have / ?%

example: for male that prefer pencils we have 30/100 = 9/? so

? = 100*9 /30 =30%

incomplete question. how do you expect anyone to you when you do not post the question in its entirety?