TM 5-6675-322-14KeystrokesDisplayL . R .-118,290.6295T h e y - i n t e r c e p t o f t h e l i n e.61.1612Slope of the line.( 6 ) L i n e a r e s t i m a t i o n.With data accumulated in registers R.0 through R.5 apredicted value for y (denoted y) can be calculated by keying in a new value for xa n d p r e s s i ng. A predicted value for x (denoted x) can be calculated bykeying in a new value for y and pressingExample:With data intact from previous example in registers R.0 through R.5to predict demand for motor fuel for the years 1980 and 2000, key in new x valuesand press. To determine the year that the demand for motor fuel is expectedt o p a s s 3 , 5 0 0 m i l l i o n b a r r e l s ,key in 3,500 (new value for y) and pressKeystrokeDisplay19802,808.6264Predicted demand in millionsof barrels for the year 1980.20004,031.8512Predicted demand in millionsof barrels for the year 2000.351,991.3041The demand is expected to pass3 , 5 0 0 m i l l i o n b a r r e l s d u r i ng1992.( 7 ) C o r r e l a t i o n c o e f f i c i e n t .Both linear regression and linear estimationpresume that the relationship between x and y data values can be approximated, tosome degree,b y a l i n e a r f u n c t i o n ( a s t r a i g h t l i n e ) . ( c o r r e l a t i o n c o e f f i c i e n t )can be used to determine how closely the data “fits” a straight line.The correla-tion coefficient can range from r = + 1 to r = - 1.At r = + 1, data falls exactlyo n t o a s t r a i g h t l i n e w i t h p o s i t i v e s l o p e .While at r = -1, data falls exactly ontoa s t r a i g h t l i n e w i t h n e g a t i v e s l o p e .A t r = 0, data cannot be approximated by as t r a i g h t l i n e .Example:To calculate the correlation coefficient for previous example press:KeystrokesD i s p l a y0.9931The data very closelyapproximates a straight line.3 - 7.OPERATION UNDER UNUSUAL CONDITIONS. This equipment is designed for operationonly in a controlled environment.3-34
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business