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%

answer set (b) 0.5, 3/4 80% is in order from least to greatest.  

step-by-step explanation:

in order to compare rational numbers to each other, it is much easier if they are in the same form.   typically, the best form in which to evaluate rational numbers is in decimals.   in order to convert a percent to a decimal, you would divide the given percentage by 100.   you can also accomplish the conversion by moving the decimal point over two places to the left.   for example, the decimal value of 80% is 80/100, or 0.8.   in order to convert a fraction to a decimal, you need to divide the numerator by the denominator.   for example, 3/4 is 0.75.   so, for choice (b) 0.5 3/4 (0.75), 80% (0.8) is the only choice in which the numbers are in order from least to greatest.  

a is the correct