A multiple choice test has four possible answers for each question. Let X be the number of correct responses in a test of 100 questions if the student simply guesses on each question. The standard deviation of X is

a. 4.33.
b. 18.75.
c. 0.433.

a. 4.33.

Step-by-step explanation:

If there is only one correct answer out of four alternatives, the expected proportion of correct answers is p =0.25

Sample size (n) = 100 questions

The standard deviation of a proportion 'p' is given by:

Applying the given data:

If X is the number of correct responses in 100 guesses, the standard deviation of X is:

The standard deviation of X is 4.33 questions.

is there any attachment? what are the equations?

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is