1 1 28 005 z 05 1 645 0025 z 025 1 96 001 z 01 2 33

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1=1.280.05z0.05=1.6450.025z0.025=1.960.01z0.01=2.33To find az-score (critical value) using TI83/84 plusPress2ndand thenvarsto bring the distributions menu.SelectinvNormand plug the value of the area to the left of the criticalvalue you are looking for.Hitenterto get the desired critical value.You can also use Table A2; see your notes of MAT121).A. Bourhim (Syracuse University)Testing a Claim About a ProportionFall 20154 / 6
ExampleA study shows that 57 out of 104 pregnant women correctly guessed the sexof their babies. Use a 0.05 significance level and this sample to test the claimthat the success rate of such guesses is 50%.
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ExampleA claim said that more that 75%of adults always wear a seat belt in the frontseat. A Harris poll of 1012 adults resulted in 870 who say that they alwayswear a seat belt in front seat. Use a 0.01 significance level and this sample totest the given claim.
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Conclusion about a claimWording of Final Conclusion Figure 7-7 A. Bourhim (Syracuse University)Testing a Claim About a ProportionFall 20157 / 6