Page 145: Interpreting Results

NOTES: Interpreting Results

Error bars help us to evaluate the precision of a data set and
determine whether the data is conclusive and reliable.

▫Shorter error bars = more precise data

▫Longer error bars = less precise data

▫If the error bars do notoverlap, the data
sets can be considered conclusively
different.

▫If the error bars overlap, there was not a
significant difference between the data
points, and therefore the different data
sets cannot be considered conclusively
different.

Averages

Error Bars

NOTES: Error Bars

Multiple Choice

Is the data on the previous slide conclusively different?

• Yes, the error bars don't overlap

• Yes, the error bars overlap.

• No, the error bars don't overlap.

• No, the error bars overlap

To construct errors bars we use two measurements…

1.

Average of the data set

2.

Standard deviation

NOTES: Error Bars

●

Standard deviation gives a sense of how spread out the data is for
a give data set

●

It helps us see how varied the data is from the average

68% of data points within a data set fall within the standard deviation.

We will use a computer to calculate the standard deviation

NOTES: Standard Deviation

Multiple Choice

How do you calculate the average of a dataset?

• Add all the numbers up and divide by the amount of numbers there are

• Add all the numbers up and multiply by the amount of numbers there are

• Subtract the largest number from the smallest number

• Arrange the numbers from least to greatest and choose the number in the middle

To calculate the TOP of an error bar…

AVERAGE + STANDARD DEVIATION

To calculate the BOTTOM of an error bar…

AVERAGE – STANDARD DEVIATION

Averages

Error Bars

NOTES: Error Bars

Sample 1

●AVG = 9.00

●SD = 3

Sample 2

●AVG = 11.00

●SD = 4

Open Ended

Do you think the data from our rocket lab will be conclusively different? Justify your answer.