Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

A study estimated how a person\'s social status (rated on a scale where 100 indi

ID: 2872899 • Letter: A

Question

A study estimated how a person's social status (rated on a scale where 100 indicates the status of a college graduate) depended upon income. Based on this study, with an income of i thousand dollars, a person's status is S(i) = 17.5(i 1)0.53. † Find

S'(21). (Round your answer to two decimal places.)

S'(21) = _____



Interpret your answer.

___At an income of $21,000 social status increases by this amount per additional $1000 of income.

___At an income of $21,000 social status decreases by this amount per additional $1000 of income.    

___At an income of $21,000 social status does not change.

___At an income of $21,000 social status increases by this amount per additional $100 of income.

___At an income of $21,000 social status decreases by this amount per additional $100 of income.

Explanation / Answer

Answer:

With an income of i thousand dollars, a person's status is S(i) = 17.5(i 1)0.53

differentiate with respect to i, we get

S'(i) = (17.5)(0.53)(i 1)0.53-1

S'(i) = (17.5)(0.53)(i 1)-0.47

put i=21 we get

S'(21) = (17.5)(0.53)(21 1)-0.47

S'(21) = (17.5)(0.53)(20)-0.47

S'(21) = 2.27

(1) At an income of $21,000 social status increases by this amount per additional $1000 of income is

S(22) = 17.5(22 1)0.53

S(22) = 17.5(21)0.53

S(22)=87.86

But S(21)=85.62

Hence the social status is increased by 87.86-85.62=2.24.

(b) At an income of $ 21000, we have the social status of the person is S(21)=85.62 and S'(21)=2.27

(C) At an income of $21,000 social status increases by this amount per additional $100 of income is

S(21.1) = 17.5(21.1 1)0.53

    S(21.1) = 85.84