Manuals/calci/FORECAST

FORECAST(n,y,x)

• $n$ is the data point .
• $y$ is the dependent array of data.
• $x$ is the independent array of data.

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 $FORECAST(n,y,x),n$ is the data point to predict a value. $y$ is the dependent array of data to predict the $y$-value and $x$ 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 nonnumeric.
 2. The values of x and y are empty or contain a different number of data points.
 3. The variance of x is zero.

Examples

1. y={5,9,11,18,32,4}

x={ FORECAST(26,B1:B6,C1:C6)=13.16666667

1. y={}

x={-42,34,-13,25} FORECAST(18,C5:C8,D5:D8)=2.119541779

1. y={51,14,0,60}

x={46,-1,29,18} FORECAST(24,D1:D4,E1:E4)=31.71054889

1. y={2,5,9,17}

x={4,14,28} FORECAST(10,B1:B4,C1:C3)=NAN.

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.

See Also

• GROWTH
• LINEST
• LOGEST