A student does an experiment to determine the specific heat of iron metal. The s

Question

A student does an experiment to determine the specific heat of iron metal. The student repeats the experiment 5 times and gets the following values for specific heat (all in J/g C: 0.463, 0.449, 0.451,0.427, and 0.480. The accepted value for the specific heat of iron is 0.450 J/g C.
a) Calculate the student's percent error. Does the percent error evaluate the accuracy or the precision of the student's measurements? Explain
b) Calculate the standard deviation for the student's data set. Does the standard deviation evaluate the accuracy or the precision of the student's measurements? Explain.

Explanation / Answer

Percentage error = (Error/ Theoretical value)* 100

where error= experimental value - theoretical value

Theoretical value: 0.450 J/gC

for first trial: percentage error : [(0.463 -0.450)/0.450]*100 = 2.9%

similary you can do for the rest of the trials.

For standard deviation, first calculate the arithmetic mean of the data

Mean= 0.454 J/gC

Then make a table for d and d2

d: 0.009 -0.005 -0.003 -0.027 0.026

d2: 0.000081 0.000025 0.00009 0.000729 0.000676

Add up all the values of d2 we get= 0.001601

standard deviation= square root(0.001601/4) = sqrt(0.0004)= 0.02

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