0.2 B2, B3: Accuracy, Precision, And Units

1.

The chart shows the density of seawater samples collected from the Gulf of Mexico by four different groups. Which group's data are most precise?

Group 1

Group 2

Group 3

Group 4

Could calculate and find an overall difference for group 2 per trial compared to average is about 0.001

Explanation

Could calculate and find an overall difference for group 2 per trial compared to average is about 0.001

2. A student observes a garden plot. Several plants shaded by a tree are not as large as those of the same species growing in the full sun. The student asks, "Why are the plants growing in the shade smaller than the plants growing in the sun?" Which is the most reasonable hypothesis to explain the student's observations?

The tree removes water from the soil. The drier soil limits the growth of those plants growing near the tree.

The tree removes minerals from the soil. The mineral-reduced soil limits the growth of those plants growing near the tree.

The tree blocks sunlight, lowering the light level in the shaded area. This limits the growth of this plant species, which grows best in direct sunlight.

Answer option 4

The most reasonable hypothesis to explain the student's observations is that the tree blocks sunlight, lowering the light level in the shaded area. This limitation of light in the shaded area inhibits the growth of the plant species, which typically thrives in direct sunlight.

Explanation

The most reasonable hypothesis to explain the student's observations is that the tree blocks sunlight, lowering the light level in the shaded area. This limitation of light in the shaded area inhibits the growth of the plant species, which typically thrives in direct sunlight.

3. Which of the following will allow measurement of a liquid's volume with the greatest precision?

50 mL cylinder graduated in 1 mL increments

100 mL cylinder graduated in 0.5 mL increments

100 mL cylinder graduated in 1 mL increments

200 mL cylinder graduated in 5 mL increments

Precision = small increments

Explanation

Precision = small increments

4. A student performed an analysis of a sample for its calcium content and got the following results: 14.92% 14.91% 14.88% 14.91% The actual amount of calcium in the sample is 14.90%. What conclusions can you draw about the accuracy and precision of these results?

While precise, these results are not accurate.

While accurate, these results are not accurate.

These results are both accurate and precise.

These results are neither accurate nor precise.

The given results are both accurate and precise because they are very close to the actual amount of calcium in the sample (14.90%). Accuracy refers to how close a measurement is to the true value, and in this case, the results are within a very small range of the actual value. Precision, on the other hand, refers to how close multiple measurements are to each other, and in this case, the results are all within a small range of each other. Therefore, the results are both accurate and precise.

Explanation

The given results are both accurate and precise because they are very close to the actual amount of calcium in the sample (14.90%). Accuracy refers to how close a measurement is to the true value, and in this case, the results are within a very small range of the actual value. Precision, on the other hand, refers to how close multiple measurements are to each other, and in this case, the results are all within a small range of each other. Therefore, the results are both accurate and precise.

5. A student needs to collect quantitative data about the pendulum lab. Which of the following is NOT considered quantitative data?

Length of string

Initial dropping height

Period of the swing

Material used to change mass

Quantitative data refers to numerical information that can be measured or counted. In this case, all the options except "Material used to change mass" involve measurable quantities. The length of the string, initial dropping height, and period of the swing can all be measured using standard units of measurement. However, the material used to change mass is not a numerical value, but rather a qualitative characteristic. It does not provide a measurable quantity and therefore is not considered quantitative data.

Explanation

Quantitative data refers to numerical information that can be measured or counted. In this case, all the options except "Material used to change mass" involve measurable quantities. The length of the string, initial dropping height, and period of the swing can all be measured using standard units of measurement. However, the material used to change mass is not a numerical value, but rather a qualitative characteristic. It does not provide a measurable quantity and therefore is not considered quantitative data.

6. In our pendulum lab our hypotheses could have arisen from....

Observations

Prior Knowledge

Inferences

All of the above

All of the above is the correct answer because in a pendulum lab, hypotheses can arise from observations, prior knowledge, and inferences. Observations of the pendulum's motion and behavior can lead to the formulation of hypotheses. Prior knowledge about pendulums and their properties can also contribute to hypotheses. Additionally, inferences made based on the observed data and prior knowledge can generate hypotheses. Therefore, all of these factors can play a role in the development of hypotheses in a pendulum lab.

Explanation

All of the above is the correct answer because in a pendulum lab, hypotheses can arise from observations, prior knowledge, and inferences. Observations of the pendulum's motion and behavior can lead to the formulation of hypotheses. Prior knowledge about pendulums and their properties can also contribute to hypotheses. Additionally, inferences made based on the observed data and prior knowledge can generate hypotheses. Therefore, all of these factors can play a role in the development of hypotheses in a pendulum lab.

7. Which tool below is most precise?

Trial	Volume Shown by Graduated Cylinder	Volume Shown by the Buret
1	25 mL	26.54 mL
2	25 mL	26.51 mL
3	25 mL	26.60 mL
4	25 mL	26.49 mL
5	25 mL	26.57 mL
Average	25 mL	26.54 mL

Graduated Cylinder because it is closest to the actual answer

Buret because it has the smallest increments.

Graduated Cylinder because it rounds to a whole number

Buret because it is closest to the actual answer.

not-available-via-ai

Explanation

not-available-via-ai

8. In the pendulum lab, it was important that we began by....

Making a hypothesis

Making observations

Checking precision of testing instruments

Generating a testable question

In the pendulum lab, it was important to begin by making observations because this allows us to gather information and data about the pendulum's behavior and characteristics. By carefully observing the pendulum's motion, we can establish a baseline understanding of its behavior before conducting any further experiments or tests. This initial step helps to ensure that our subsequent hypothesis, testable question, and precision of testing instruments are based on accurate and reliable observations.

Explanation

In the pendulum lab, it was important to begin by making observations because this allows us to gather information and data about the pendulum's behavior and characteristics. By carefully observing the pendulum's motion, we can establish a baseline understanding of its behavior before conducting any further experiments or tests. This initial step helps to ensure that our subsequent hypothesis, testable question, and precision of testing instruments are based on accurate and reliable observations.