For each student in a certain class, a teacher adjusted the student's test score using the formula y = 0.8x + 20, where x is the student's original test score and y is the student's adjusted test score. If the standard deviation of the original test scores of the students in the class was 20, what was the standard deviation of the adjusted test scores of the students in the class?

The question is missing alternatives. The complete question is here.

For each student in a certain class, a teacher adjusted the student's test score using the formula y = 0.8x + 20, where x is the student's original test score and y is the student's adjusted test score. If the standard deviation of the original test scores of the students in the class was 20, what was the standard deviation of the adjusted test scores of the students in the class?

A. 12

B. 16

C. 28

D. 36

E. 40

B. 16

Step-by-step explanation: If you add a constant to each number at the data set, standard deviation doesn't change. However, multiplying each data in the data set by a constant, also multiplies the standard deviation by that constant.

That being said, the formulafor the adjusted test score is

y = 0.8x + 20

Adding 20 to each data doesn't change standard deviation but multiplying by 0.8 changes it.

So, the new standard deviation is

σ = 20*0.8 = 16

Standard Deviation for the adjusted test scores of the students is 16.

in the attachment.   i didn't see your choices.   the word which means there is choices.

step-by-step explanation:

(x,y)

x tells you how much left or right you go from the origin

y tells you how much down or up you go from the origin

so for example (-3,2), you go left 3 and up twice. i denoted which of the ordered pairs is which in my graph.

not sure but it may be b, as i said i'm not sure.