HP 33s Scientific manual 11-8Statistical Operations, Example Curve Fitting, Nitrogen Applied

„To find an estimated value for x (or y), key in a given hypothetical value for y

(or x), then press	{ ˆ } (or	{ ˆ }).
	º	¸

„ To find the values that define the line that best fits your data, press followed by {T}, {P}, or {E}.

Example: Curve Fitting.

The yield of a new variety of rice depends on its rate of fertilization with nitrogen. For the following data, determine the linear relationship: the correlation coefficient, the slope, and the y–intercept.

X, Nitrogen Applied	0.00	20.00	40.00	60.00	80.00
(kg per hectare)
Y, Grain Yield	4.63	5.78	6.61	7.21	7.78
(metric tons per hectare)

Keys:	Display:
{c{´}	
￿ 4.63 ‘0 	
￿ 5.78 ‘20 	
￿ 6.61 ‘40 	
￿ 7.21 ‘60 	)
	)
￿ 7.78 ‘80 	) 
	)
{T}	ˆ ˆ T P E
	º ¸

)

—	ˆ	ˆ	T P E	
	º	¸
	) 
—	ˆ	ˆ	T PE		
	º	¸

) 

Description:

Clears all previous statistical data.

Enters data; displays n.

Five data pairs entered.

Displays linear–regression menu.

Correlation coefficient; data closely approximate a straight line.

Slope of the line.

y–intercept.

11–8Statistical Operations