HP 50g Graphing Calculator User Manual

Page 607

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background image

Page 18-40

values

⎯x

1

and

⎯x

2

, and standard deviations s

1

and s

2

. If the populations

standard deviations corresponding to the samples,

σ

1

and

σ

2

, are known, or if

n

1

> 30 and n

2

> 30 (large samples), the test statistic to be used is

If n

1

< 30 or n

2

< 30 (at least one small sample), use the following test statistic:

Two-sided hypothesis
If the alternative hypothesis is a two-sided hypothesis, i.e., H

1

:

μ

1

-

μ

2

≠ δ, The P-

value for this test is calculated as

Θ If using z,

P-value = 2

⋅UTPN(0,1, |z

o

|)

Θ If using t,

P-value = 2

⋅UTPT(ν,|t

o

|)

with the degrees of freedom for the t-distribution given by

ν = n

1

+ n

2

- 2. The

test criteria are

Θ Reject H

o

if P-value <

α

Θ Do not reject H

o

if P-value >

α.

One-sided hypothesis
If the alternative hypothesis is a two-sided hypothesis, i.e., H

1

:

μ

1

-

μ

2

<

δ, or,

H

1

:

μ

1

-

μ

2

<

δ,, the P-value for this test is calculated as:

Θ If using z,

P-value = UTPN(0,1, |z

o

|)

Θ If using t,

P-value = UTPT(

ν,|t

o

|)

2

2

2

1

2

1

2

1

)

(

n

n

x

x

z

o

σ

σ

δ

+

=

2

1

2

1

2

1

2

2

2

2

1

1

2

1

)

2

(

)

1

(

)

1

(

)

(

n

n

n

n

n

n

s

n

s

n

x

x

t

+

+

+

=

δ

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