In performing a sequence of experiments

[sserendipty]

In performing a sequence of experiments, a scientist made 20 measurements. The average

(arithmetic mean) of these measurements was 34. For security reasons the scientist coded the

data by multiplying each of the measurements by 10 and then adding 40 to each product.

What is the average of the coded measurements?

 

(A) 1,140

(B) 380

© 342

(D) 57

(E) 19

 

Answer:

B

 

 

 

[Brent Hanneson]

In performing a sequence of experiments, a scientist made 20 measurements. The average

(arithmetic mean) of these measurements was 34. For security reasons the scientist coded the

data by multiplying each of the measurements by 10 and then adding 40 to each product.

What is the average of the coded measurements?

 

(A) 1,140

(B) 380

© 342

(D) 57

(E) 19

 

Answer:

B

 

A quick solution is to say that the original 20 measurements were all 34

That is {34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34, 34}

These values definitely have an average of 34

 

 

For security reasons the scientist coded the data by multiplying each of the measurements by 10 and then adding 40 to each product.

34 times 10 equals 340. Add 40 to get 380

So, the 20 coded values are {380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380, 380}

New average = 380

Answer: B

 

Cheers,

Brent