The question is missing the data sets.
This is the complete question:
A single penny has a mass of 2.5 g. Abbie and James
each measure the mass of a penny multiple times. Which statement about
these data sets is true?
O Abbie's measurements are both more accurate
and more precise than James'.
O Abbie's measurements are more accurate,
but less precise, than James'.
O Abbie's measurements are more precise,
but less accurate, than James'.
O Abbie’s measurements are both less
accurate and less precise than James'.
Penny masses (g)
Abbie’s data
2.5, 2.4, 2.3, 2.4, 2.5, 2.6, 2.6
James’ data
2.4, 3.0, 3.3, 2.2, 2.9, 3.8, 2.9
Answer: first option, Abbie's measurements are both more accurate
and more precise than James'.
Explanation:
1) To answer this question, you first must understand the difference between precision and accuracy.
<span>Accuracy is how close the data are to the true or accepted value.
</span>
<span>Precision is how close are the data among them, this is the reproducibility of the values.</span>
Then, you can measure the accuracy by comparing the means (averages) with the actual mass of a penny 2.5 g.
And you measure the precision by comparing a measure of spread, as it can be the standard deviation.
2) These are the calculations:
Abbie’s data
Average: ∑ of the values / number of values
Average = [2.5 + 2.4 + 2.3 + 2.4 + 2.5 + 2.6 + 2.6 ] / 7 = 2.47 ≈ 2.5
Standard deviation: √ [ ∑ (x - mean)² / (n - 1) ] = 0.11
James’ data
Average = [2.4 + 3.0 + 3.3 + 2.2 + 2.9 + 3.8 + 2.9] / 7 = 2.56 ≈ 2.6
Standard deviation = 0.53
3) Conclusions:
1) The average of Abbie's data are closer to the accepted value 2.5g, so they are more accurate.
2) The standard deviation of Abbie's data is smaller than that of Jame's data, so the Abbie's data are more precise.
Answer:
Double covalent bonds in carbon dioxide
Explanation:
The compound shown in the image is carbon dioxide. Carbon, the central atom in the molecule is bonded to two oxygen atoms. Carbon shares four electrons with each oxygen atom. The carbon atom is sp hybridized while the two oxygen atoms are sp2 hybridized.
The carbon atom is attached to each oxygen atom via a double covalent bond which implies the sharing of four electrons. Two electrons form the sigma bond while the other two electrons are shared in the pi bond thereby giving the double covalent bind indicated by the lines in the structure of the molecule.
Your skeletal system consists of all the 206 bones and the 360 joints in the human body. This includes the cells, protein fibers and minerals that make up your bones.
Answer:
The volume of the sheet metal = 0.58 cm³
<em>Note: The question is incomplete. A similar complete question is given below:</em>
<em>a 7.50 g piece of metal was rolled into a thin sheet measuring 24.0 cm × 30.0 cm</em>
<em>the density of the metal is 12.86 g/cm</em>
<em>calculate the volume of the sheet of metal</em>
Explanation:
The mass of a substance is the quantity of matter present in that substance
The volume of a substance is amount of space the substance occupies
Density of a substance is the ratio of its mass and the volume it occupies. It is a measure of how compact a body is.
From definition above;
Density = mass/volume
Therefore, volume = mass/density
mass of thin sheet = 7.50 g
density = 12.86 g/cm³
Volume = 7.50 g / 12.86 gcm⁻³
Volume = 0.58 cm³
Therefore, the volume of the sheet metal = 0.58 cm³
Answer:
Mass of carbon dioxide = 7.48 g
Explanation:
Given data:
Mass of lithium carbonate = 12.5 g
Mass of carbon dioxide produced = ?
Solution:
Chemical equation:
Li₂CO₃ → Li₂O + CO₂
Number of moles of Li₂CO₃:
Number of moles = mass/ molar mass
Number of moles = 12.5 g /73.89 g/mol
Number of moles = 0.17 mol
Now we will compare the moles of Li₂CO₃ with CO₂.
Li₂CO₃ : CO₂
1 : 1
0.17 : 0.17
Mass of carbon dioxide:
Mass of carbon dioxide = number of moles × molar mass
Mass of carbon dioxide = 0.17 mol × 44 g/mol
Mass of carbon dioxide = 7.48 g