Question

Precision Problems:

A group of students worked in separate teams to measure the length of an object.
Here are their data:
Team 1
2.65 cm
Team 2
2.75 cm
Team 3
2.80 cm
Team 4
2.77 cm
Team 5
2.60 cm
Team 6
2.65 cm
Team 7
2.68 cm
I
cm.
• The average length is
This is the mean or average.
cm.
• Subtract the highest value from the lowest value:
This is the range or spread.
• Divide this number by 2:
cm.
This is the approximate range from the average.
• The precision of the measurement can be shown as average range.
The precision of the measurement was
cm.
Demystifying Scientific Data: RET 2006, Rev 2
25

Answer 1

`Precision = 2.70 \± 0.1\ cm`

Step-by-step explanation:

Given

The data in the table

Required

Follow the steps appended to the question;

Step 1: Calculate the Mean or Average

Mean = Summation of lengths divided by number of teams;

`Mean = (2.65 + 2.75 + 2.80 + 2.77 + 2.60 + 2.65 + 2.68)/(7)\ cm`

`Mean = (18.9)/(7)\ cm`

`Mean = 2.70\ cm`

Step 2: Get The Range

`Range = Highest - Lowest`

`Range = 2.80cm - 2.60cm`

`Range = 0.2\ cm`

Step 3: Divide Range by 2

`Approximate\ Range = (1)/(2)Range`

`Approximate\ Range = (1)/(2) * 0.2\ cm`

`Approximate\ Range = 0.1\ cm`

Step 4: Determine the Precision

`Precision = Average \± Approximate\ Range`

Substitute 2.70 for Average and 0.1 for Approximate Range

`Precision = 2.70 \± 0.1\ cm`