Question

claim: fewer than 90% of adults have a cell phone. in a reputable poll of 1152 adults, 81% said that they have a cell phone. find the value of the test statistic. the value of the test statistic is (round to two decimal places as needed.)

Explanation:

Step1: Identify the values

Given \(n = 1152\), \(\hat{p}=0.81\), \(p = 0.90\), \(q=1 - p=0.10\)

Step2: Calculate the test - statistic formula

The formula for the test - statistic \(z\) in a proportion test is \(z=\frac{\hat{p}-p}{\sqrt{\frac{pq}{n}}}\)

Substitute the values:

$$
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$$

Answer:

\(-10.18\)