Paired sample tests, Inferences concerning one proportion – HP 50g Graphing Calculator User Manual

Page 608

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Page 18-41

The criteria to use for hypothesis testing is:

Θ Reject H

o

if P-value <

α

Θ Do not reject H

o

if P-value >

α.

Paired sample tests

When we deal with two samples of size n with paired data points, instead of
testing the null hypothesis, H

o

:

μ

1

-

μ

2

=

δ, using the mean values and standard

deviations of the two samples, we need to treat the problem as a single sample
of the differences of the paired values. In other words, generate a new random
variable X = X

1

-X

2

, and test H

o

:

μ = δ, where μ represents the mean of the

population for X. Therefore, you will need to obtain

⎯x and s for the sample of

values of x. The test should then proceed as a one-sample test using the
methods described earlier.

Inferences concerning one proportion

Suppose that we want to test the null hypothesis, H

0

: p = p

0

, where p represents

the probability of obtaining a successful outcome in any given repetition of a
Bernoulli trial. To test the hypothesis, we perform n repetitions of the
experiment, and find that k successful outcomes are recorded. Thus, an
estimate of p is given by p’ = k/n.

The variance for the sample will be estimated as s

p

2

= p’(1-p’)/n = k

⋅(n-k)/n

3

.

Assume that the Z score, Z = (p-p

0

)/s

p

, follows the standard normal distribution,

i.e., Z ~ N(0,1). The particular value of the statistic to test is z

0

= (p’-p

0

)/s

p

.

Instead of using the P-value as a criterion to accept or not accept the hypothesis,
we will use the comparison between the critical value of z0 and the value of z
corresponding to

α or α/2.

Two-tailed test
If using a two-tailed test we will find the value of z

α/2

, from

Pr[Z> z

α/2

] = 1-

Φ(z

α/2

) =

α/2, or Φ(z

α/2

) = 1-

α/2,

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