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= Homework: Pr...
Question 25, 8.1.14
HW Score: 46.61%, 34.03 of 73 points
O Points: 0 of 1
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Claim: Fewer than 95% of adults have a cell phone. In a reputable poll of 1135 adults, 90% 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.)
5/3)
2
1)
33/2)
1)
у
78/2)
3)
'1)
2)

Answer 1

Test statistic for population proportion is given by

$z=\frac{\hat{p}-p}{\sqrt[]{\frac{p(1-p)}{n}}}$

where: p is population proportion, p^ is sample proportion and n is sample size. So, the test statistic will be:

$\begin{gathered} z=\frac{0.90-0.95}{\sqrt[]{\frac{0.95(1-0.95)}{1135}}} \\ z=\frac{-0.05}{\sqrt[]{\frac{0.0475}{1135}}} \\ z=-7.728\approx-7.73 \end{gathered}$

Answer: The value of the test statistic is - 7.73