Respuesta :
The question is incomplete, here is the complete question.
A student performs an experiment to determine the density of a sugar solution. She obtains the following results: 1.11 g/mL, 1.81 g/mL, 1.95 g/mL, 1.75 g/mL. If the actual value for the density of the sugar solution is 1.75 g/mL, which statement below best describes her results?
A) Her results are precise, but not accurate.
B) Her results are accurate, but not precise.
C) Her results are both precise and accurate
D) Her results are neither precise nor accurate.
E) It isn't possible to determine with the information given.
Answer: The results are neither precise nor accurate.
Explanation:
Accuracy is defined as the closeness of a measured value to a standard or known value.
For Example: If the mass of a substance is 80 kg and one person weighed 88 kg and another person weighed 82 kg. Then, the weight measured by second person is more accurate.
Precision is defined as the closeness of two or more measurements to each other.
For Example: If you weigh a given substance ten times and you get 2.5 kg each time. Then the measurement is said to be precise.
For the given measurements:
Measurement 1, [tex]d_1[/tex] = 1.11 g/mL
Measurement 2, [tex]d_2[/tex] = 1.81 g/mL
Measurement 3, [tex]d_3[/tex] = 1.95 g/mL
Measurement 4, [tex]d_4[/tex] = 1.75 g/mL
Average value of density = [tex]\frac{d_1+d_2+d_3+d_4}{4}=\frac{1.11+1.81+1.75+1.95}{4}=1.655g/mL[/tex]
Actual value of density = 1.75 g/mL
The measured values of density are not close to each other and neither the average value is close to the actual value.
Hence, the results are neither precise nor accurate.
