As part of an experiment, a student repeatedly tests the temperature

Question

As part of an experiment, a student repeatedly tests the temperature of a light bulb. The bar graph below displays the number of readings the student recorded at various temperatures, measured in degrees Fahrenheit. What was the average temperature reading of the light bulb?

A. 110°
B. 111°
C. 112°
D. 113°
E. 114°

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Official Answer

C

CareerGeek · Answer

Average temperature =  \frac{4*110 + 3*111 + 4*112 + 113 + 2*114 + 2*115}{4 + 3 + 4 + 1 + 2 + 2} 
=  \frac{440 + 333 + 448 + 113 + 228 + 230}{16} 
=  \frac{1792}{16} = 112 °

Option C

Kinshook · Answer

Average temperature = 112 + (-4*2 - 3 + 1 + 2*2 + 2*3)/16 = 112 + 0

IMO C

ScottTargetTestPrep · Answer

The average is:

(110 x 4 + 111 x 3 + 112 x 4 + 113 + 114 x 2 + 115 x 2)/16

(440 + 333 + 448 + 113 + 228 + 230)/16 = 112

Answer: C

ocelot22 · Answer

Notice the temperature increase are in integer increments. This means that the mean=median. Therefore the mean is 112.

SiddharthR · Answer

How do you solve this question without doing the cumbersome calculation shown above ? By concept of weighted averages I was able to deduce that it could be either options A / C and then I guessed C. How can i be certain its C. Is it only by calculating the average ????

Sabby · Answer

Hi,

One way to solve it, easier and faster, is to take 110° as a base point: 110 becomes 0 and 111 becomes 1 and so on. It's always better to work with smaller numbers:

0*4+1*3+2*4+3*1+4*2+5*2
=0+3+8+3+8+10
=32

Now we have 16 readings, so the average is 32/16=+2
Therefore you need to add +2 to our base point 110° which becomes 112°

Answer C)

bumpbot · Answer

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As part of an experiment, a student repeatedly tests the temperature

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