Null Hypothesis Ho This hypothesis is the hypothesis

1. Ho: X ≤ value Ha: X > value (this will be right tailed)

Before starting, you will need the values of n, p, and q. -------------§ n

Tailed Significance Critical Level Value Left 0. 10 -1. 28 Right 0. 10 1.

7. Find the z-score (standard score). Where is it on the curve? : 8.

A medical researcher claims that less than 20% of adults in the U.

§ Since Ha is <, this is a lefttailed test, and since α =

§ Since z = -1. 25, and this is not in the rejection region,

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Null Hypothesis: Ho This hypothesis is the hypothesis you will “reject” or “fail to reject”. When written as a mathematical statement, it will have an =, ≤, or ≥ as it is a “statement of equality”. Alternative Hypothesis (Ha) This hypothesis is known as a “statement of inequality” as it will have a ≠, <, or > in a mathematical statement. While it is the Null Hypothesis you will “reject” or “fail to reject”, either hypothesis can be the “claim” in the experiment.

1. Ho: X ≤ value Ha: X > value (this will be right tailed) 2. Ho: X ≥ value Ha: X < value (this will be left tailed) 3. Ho: X = value Ha: X ≠ value (this will be two tailed)

Before starting, you will need the values of n, p, and q. -------------§ n is the sample size § p is the population parameter (this will be in the problem) § q is the value 1 - p

Tailed Significance Critical Level Value Left 0. 10 -1. 28 Right 0. 10 1. 28 Two 0. 10 ± 1. 645 Left 0. 05 -1. 645 Right 0. 05 1. 645 Two 0. 05 ± 1. 96 Left 0. 01 -2. 33 Right 0. 01 2. 33 Two 0. 01 ± 2. 575 Critical Values

7. Find the z-score (standard score). Where is it on the curve? : 8. Make a decision to “reject” or “fail to reject” H o. 9. Interpret the decision in the context of the original claim.

A medical researcher claims that less than 20% of adults in the U. S. are allergic to a medication. In a random sample of 100 adults, 15% say they have such an allergy. At α = 0. 01, is there enough evidence to support the researcher’s claim? n = 100, p = 0. 20, q = 0. 80 1. 2. np = 20, nq = 80…you can continue. Ho: p ≥ 0. 2, Ha: p < 0. 2

§ Since Ha is <, this is a lefttailed test, and since α = 0. 01, we will be using the critical value as -2. 33 (they use the symbol zo for this). § See drawing on board for sketch. § The rejection region is z < -2. 33. § The standardized test statistic (z) is:

§ Since z = -1. 25, and this is not in the rejection region, you should decide not to reject the null hypothesis. § Interpretation: There is not enough evidence to support the claim that less than 20% of adults in the U. S. are allergic to the medication.