Statistics in Physics

| rules | practice |

You are expected to be able to handle the following terms with their definitions:

BEST VALUE can be mean, mode, discrete mode (when value occurs for 67% or more), or median

mean:

for a minimum of 10 data points—- required for ten or more data values for the same measurement

standard deviation (of the population):

standard deviation (of sample):

For most situations use standard deviation of sample

Standard error:

percent standard error:

useable in any possible situation

percent relative error:

Use MiniTab (Excel does not use the correct function) to determine the confidence interval (CI) of a single variable where you have a minumum of 10 values. Enter your values into the software.

practice

Do as many of these groups as you need to do, but do Group II as a minimum. Use the following information to determine mean, mode, median, standard deviation, standard error, percent standard error, relative error, and confidence interval. What is the best value based on the measured values? Identify whether each group has been precise, accurate, both, or neither.

example I
One type of paper is supposed to be 26.7 cm long.

One group got :

26.9 cm, 26.3 cm, 26.6 cm, 26.8 cm, 26.7 cm, 26.8 cm, 26.9 cm, 26.6 cm, 27.1 cm, 26.8 cm, 26.4 cm, 26.8 cm, 26.5 cm, 26.9 cm

*example II
The mass of a book is supposed to be 527.6 g.

One group got:

525.3 g, 528.1 g, 527.3 g, 528.0 g, 528.5 g, 527.3 g, 527.8 g, 526.8 g, 526.9 g, 527.5 g, 528.1 g, 526.8 g, 527.4 g, 528.9 g, 526.7 g

*example III
your data: widths of the classroom (we don't have an accepted value - yet)

(in m)
9.250, 9.150, 8.8, 9.112, 9.12, 9.11, 9.113, 9.10, 9.96, 9.21, 10.59, 9.166, 9.12, 9.1205, 9.113, 9.130, 9.140, 9.14, 9.1395, 9.12, 9.135, 9.235, 9.235, 9.1330, 9.1350, 9.120, 9.15, 9.07, 9.1120, 9.15, 9.121, 9.1200, 9.3718

last modiified 5-30-10

key
I mean26.7 mode26.8 median26.8 BV26.8(mode/median) SD0.22 SE0.059 PSE0.22% PRE0.37% both
II mean 527.4 modes526.8 527.3 528.1 median527.4 BV527.4 SD0.88 SE0.23 PSE0.043% PRE0.033% both
III mean9.20 mode9.12 median9.1315 BV9.20 SD0.30 SE0.054 PSE 0.58%