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In-s [12.5K]
3 years ago
12

In a study of cell phone usage and brain hemispheric​ dominance, an Internet survey was​ e-mailed to 6977subjects randomly selec

ted from an online group involved with ears. There were 1337surveys returned. Use a 0.01 significance level to test the claim that the return rate is less than​ 20%. Use the​ P-value method and use the normal distribution as an approximation to the binomial distribution.Identify the null hypothesis and alternative hypothesis.
Mathematics
1 answer:
kirza4 [7]3 years ago
7 0

Answer:

Given :An Internet survey was​ e-mailed to 6977 subjects randomly selected from an online group involved with ears. There were 1337 surveys returned.

To Find : Use a 0.01 significance level to test the claim that the return rate is less than​ 20%.

Solution:

n = 6977

x = 1337

We will use one sample proportion test

\widehat{p}=\frac{x}{n}

\widehat{p}=\frac{1334}{6977}

\widehat{p}=0.1911

We are given that the claim is the return rate is less than​ 20%.

H_0:p=0.2\\H_a:p

Formula of test statistic = \frac{\widehat{p}-p}{\sqrt{\frac{p(1-p)}{n}}}

                                       = \frac{0.1911-0.2}{\sqrt{\frac{0.2(1-0.2)}{6977}}}

                                       = −1.858

Refer the z table

P(z<-1.85)=0.0332

Significance level = 0.01=α

Since p value > α

So, we accept the null hypothesis .

So,the claim that the return rate is less than​ 20% is false.

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Step-by-step explanation:

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Required

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The equations are:

x + y = 160 --- (1)

5x + 15y = 1850 --- (2)

Divide (2) through by 5

x + 3y = 370 --- (3)

Subtract (1) from (3)

x - x + 3y - y = 370 - 160

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Make x the subject

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Hence:

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An experience bricklayer can construct a small wall in 3 hours. An apprentice can complete the job in 5 hours. Find how long it
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If the bricklayer can construct the wall in its entirety in 3 hours, then he can get 1/3 of the job done in an hour.

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