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HP 30S
 Statistics – Linear Regression 
 
 
 
 
Linear Regression 
 
Practice Solving Linear Regression Problems 

 
 

 

 

 
 

 

 

 
 

 

 

 
 

 

 

 
 

 

 

 
 

 

 

 
 

 

 

 
 

 

 

 

Summary of Contents for HP 30S

Page 1: ...hp calculators HP 30S Statistics Linear Regression Linear Regression Practice Solving Linear Regression Problems ...

Page 2: ...greement between the x and y variables and is given by n y y n x x n y x y x r i i i i i i i i 2 2 2 2 When r is positive the correlation is positive which means that high values of one variable correspond to high values of the other Conversely if r is negative then the correlation is negative low values of one variable correspond to high values of the other An important property of r is that 1 1 ...

Page 3: ...ressed to two decimal digits a 1 22 and b 0 85 therefore the regression line is The correlation coefficient is 0 91 which means that the correlation is positive and that it is quite a good fit since r is close to 1 However exactly how far away from this value the correlation can be and the equation still be considered a good predictor is certainly a matter of debate x y 85 0 22 1 Example 2 If the ...

Page 4: ... 5 9 To find press y 5 10 b to select y10 5y y Answer According to the new regression the predicted value is 9 88 grams The regression line is now where x is still the amount of chemical added and y is the concentration which y x 98 0 38 0 is not the same as before y x 18 1 44 1 Example 5 By polling fifty people a survey taker obtained the following data and 3333 i x 9 459 yi 231933 2 i x 57 4308 ...

Page 5: ...s that point 610 15 6 is anomalous and is consequently removed from the data set To do so press Figure 1 a seven times and e NB not o The new correlation coefficient is displayed as above i e by pressing b and then the left arrow key six times Answer r 0 9997 so there s strong evidence that the relation is linear The regression line is x y 01 0 03 8 Example 7 Find the power curve that best fits th...

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