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Trend-line Analysis
Ina trend-line analysis, you are performing a linear regression
calculation on datathat is collected at regular, sequential
intervals. Each newx valueis one greater than the previous x
value. The calculator automatically incrementstheinitial
valueof x so that you do nothaveto enter subsequent x
values.
Entering
To enterdata for a trend-line analysis:
the Data
1, Enter the first data value as describedin ''Entering
and Removing 2-Variable Data."'
> Enterxandpress
> Entery and press
2. Enteronly they value for the remaining data values.
The calculator automatically enters the
corresponding x.
Note: If any of the remaining data values are not
sequential, be sure to reenterthe newx value.
A trendline appliesonly to single occurrencedata, so the
<FRQ) keyis notpart of trendline data entry.
Removing
To remove datapairjustafterit is entered, press
Data
| . The calculator removesthelast x and y values
and automatically decrements the contents ofthet-
register in preparationfor the next entry.
Toremovean entry ata later time, use the procedure
described in "Entering and Removing 2-Variable Data."
Example
A companyhas the following annual profits:
Year (x)
Profit in Millions(y)
1971
-2.1
1972
-0.3
1973
0.8
1974—80
inactive
1981
2.9
1982
2.8
1983
3.6
1984
4.0
1985
4.7
(continued)
3-16
Statistics Operations
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