Precision and accuracy

a) Grab 5 equal size sheets.

b) Draw a line by hand (Without a ruler) that you estimate to be 10.0 cm, cover the sheet, so you cannot see it.

c) Repeat drawing of what you estimate to be 10.0 cm long lines on 3 more sheets, each time cover the sheet so that you will not see your previous estimates.

d) Now measure the length of each line with your metric ruler. Enter these measurements in the data table below. Remember that you will have 2 digits to the right of the decimal.

e) Hide the first four sheets from sight. Repeat the above process with the remaining 4 pieces of paper, each time turning them over so that you cannot see the other estimates.

f) Again measure the actual lengths.

g) Enter the data for both trails on the data tables below.

Measured Length(cm) % Error= 10.0-measure / 10.0

Trial 1-

Trial 2-

Trial 3-

Trial 4-

Trial 5-

Average:

a) Grab 5 equal size sheets.

b) Draw a line by hand (Without a ruler) that you estimate to be 10.0 cm, cover the sheet, so you cannot see it.

c) Repeat drawing of what you estimate to be 10.0 cm long lines on 3 more sheets, each time cover the sheet so that you will not see your previous estimates.

d) Now measure the length of each line with your metric ruler. Enter these measurements in the data table below. Remember that you will have 2 digits to the right of the decimal.

e) Hide the first four sheets from sight. Repeat the above process with the remaining 4 pieces of paper, each time turning them over so that you cannot see the other estimates.

f) Again measure the actual lengths.

g) Enter the data for both trails on the data tables below.

Measured Length(cm) % Error= 15.0-measure / 15.0

Trial 1-

Trial 2-

Trial 3-

Trial 4-

Trial 5-

Average:

Questions

1. Did your accuracy improve with practice?
2. Calculate the average deviation of your measured times.