AP Statistics 2017

(Marvins-Underground-K-12) #1
(This   can also    be  done    using   1-PropZTest in  the STAT    TESTS menu  of  the TI-83/84.)
IV . The question asked about both α = 0.05 and α = 0.01. We note that this finding would have
been significant at α = 0.05 but not at α = 0.01. For the two significance levels, the solutions
would look something like this:

(1)     Since   the P   -value  =   0.042   <   α   =   0.05,   we  reject  the null    hypothesis. We  have    evidence
that the true proportion of heads is greater than 0.50.

(2)     Since   the P   -value  =   0.042   >   α   =   0.01,   we  fail    to  reject  the null    hypothesis. We  do  not
have convincing evidence that the true proportion of heads is greater than 0.50.

Inference for the Difference Between Two Population Proportions


The logic behind inference for two population proportions is the same as for the others we have studied.
As with the one-sample case, there are some differences between z -intervals and z -tests in terms of the
computation of the standard error. The following table gives the essential details.


example: Two    concentrations  of  a   new vaccine designed    to  prevent infection   are developed   and a
study is conducted to determine if they differ in their effectiveness. The results from the study
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