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I am having trouble knowing how to use SD and Avg to figure out accuracy and per

ID: 704811 • Letter: I

Question

I am having trouble knowing how to use SD and Avg to figure out accuracy and percision and draw conclusions about the data **also how do I know what data to exclude? should i use percent error ? please explain this more in depth

Show ALL Work For Full Credit! Please write multiple choice answers in the space provided Density and Data Analysis 1. Two C127 students each determine the density of ethanol using the same procedure. Tom's four data points have an average of 0.671 and a standard deviation of 0.017, Latisha's four data points have an average of 0.741 and a standard deviation of 0.038. If the actual density of ethanol is 0.789 then data is more accurate, and is more precise. (4pts) A. Tom's, Tom's B. Tom's, Latisha's C Latisha's, Tom's D. ahs, Answer 2. Tom's four data points are 0.655, 0.688, 0.682, and 0.657. Should Tom exclude any of his data? Explain your answer(10 pts)

Explanation / Answer

1. C) Latisha, Tom

Accuracy is when the average obtained is nearer to the actual value. Here actual value is 0.789 and Latisha's value is 0.741 which is nearer to the actual value as compared to Tom's 0.671. Precision is when all the observations are nearer to each other. This is found by standard deviation. The more the deviation, more farther are the values. Hence if SD is lesser, precision is more.

2. Tom cannot exclude any because there are two pairs of observations that are close to each other. Even if he excludes one observation it won't make much difference. He can eliminate 2 observations but he won't know which ones to eliminate because he wouldn't know the right answer.