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Drawing an exponential regression graph, B · x, 1n – 2 – Casio CLASSPAD 330 3.04 User Manual

Page 409: Ln ( y, Ln ( a ) + b·x

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Drawing an Exponential Regression Graph (

y

=

a

·

e

b

·

x

)

Exponential regression can be used when

y

is proportional to the exponential function of

x

. The normal exponential regression formula is

y

=

a

·

e

b

·

x

. If we obtain the logarithms of

both sides, we get ln(

y

) = ln(

a

) +

b

·

x

. Next, if we say that Y = ln(

y

) and A = In(

a

), the formula

corresponds to the linear regression formula Y = A +

b

·

x

.

S ClassPad Operation

Start the graphing operation from the Statistics application’s Graph window or List window.

From the Graph window

Tap [Calc] [Exponential Reg] [OK] [OK] .

From the List window

Tap [SetGraph][Setting...], or '.

On the Set StatGraphs dialog box that appears, configure a StatGraph setup with the
setting shown below, and then tap [Set].

Type:

ExpR

Tap

x to draw the graph.

7-5-10

Graphing Paired-Variable Statistical Data

The following is the exponential regression model formula in this case.

y

=

a

·

e

b

·

x

a

: regression

coefficient

b

:

regression constant term

r

: correlation

coefficient

r

2

:

coefficient of determination

MSe

: mean square error

• MSe

=

1

n

– 2

i

=1

n

(ln (y

i

) – (ln (a) + b·x

i

))

2

··