Manuals/calci/FORECAST

FORECAST (x,KnownYs,KnownXs)

• $x$ is the data point .
• $KnownYs$ is the dependent array of data.
• $KnownXs$ is the independent array of data.
• Returns a value along a linear trend.

Description

• This function gives the predicted value of the dependent variable for the specific value $x$, of the independent variable by using a least squares linear regression to predict $y$ values from $x$ values.
• In $FORECAST(x,KnownYs,KnownXs)$, $x$ is the data point to predict a value.
• $KnownYs$ is the dependent array of data to predict the $y$-value and $KnownXs$ is the independent array of data to predict the $y$-value.
• The formula for $FORECAST$ is $a+bx$
• where $a={\bar {y}}-b{\bar {x}}$ and $b={\frac {\sum (x-{\bar {x}})(y-{\bar {y}})}{\sum (x-{\bar {x}})^{2}}}$.
• Here ${\bar {x}}$ and ${\bar {y}}$ are the sample means of $x$ and $y$.
• This function will give the result as error when

 1. Any one of the value is non-numeric.
 2. The values of $KnownXs$ and $KnownYs$ are empty or contain a different number of data points.
 3. The variance of $x$ is zero.

ZOS

• The syntax is to calculate this function in ZOS is $FORECAST(x,KnownYs,KnownXs)$
  • $x$ is the data points.
• For e.g.,FORECAST(30,[10,12,16,21,35],[9,14,23,39,76])
• FORECAST(61,[22..28],[43..49])

Examples

Spreadsheet

	A	B	C	D	E	F
1	5	30	-28	-42	51	46
2	9	32	-18	34	14	-1
3	11	15	35	-13	0	29
4	18	28	12	25	60	18
5	32	41	2	5	9	17
6	4	10	4	14	28

1. =FORECAST(26,A1:A6,B1:B6) = 13.16666667
2. =FORECAST(18,C1:C4,D1:D4) = 2.119541779
3. =FORECAST(24,E1:E4,F1:F4) = 31.71054889
4. =FORECAST(10,C5:F5,C6:E6) = NAN.

Related Videos

FORECAST

See Also

• GROWTH
• LINEST
• LOGEST

References

• FORECAST

• List of Main Z Functions

• Z3 home