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2 years ago

What’s the radius of a sphere with a surface area of 4pie square feet

Mathematics

1 answer:

In-s [12.5K]2 years ago

6 0

Set up an equation

$4\pi r^2$ = $4\pi$

Solve.

$4\pi /4\pi = 1$

$r^2 = 1$

$r = \sqrt{1}$

$r = 1$

Answer

$r = 1$

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4. Is rap music more popular among young Indians than among young Asians? A sample survey compared 634 randomly chosen Indians a

bulgar [2K]

Answer:

H0 is accepted

there is no difference between the proportions of Indian and Asian young people who listen to rap music every day.

Step-by-step explanation:

Given a sample survey compared 634 randomly chosen Indians aged 15 to 25 with 567 randomly selected Asians in the same age group.

$p_{1} = \frac{368}{634} =0.580$

It found that 368 of the Indians and 130 Asians listened to rap music every day.

$p_{2} = \frac{130}{567} =0.229$

Null hypothesis H0: there is no difference between the proportions of Indian and Asian young people who listen to rap every day.

$p_{1} = p_{2}$

Alternative hypothesis:- $p_{1} \neq p_{2}$

Level of significance α = 0.05

The test of statistic

$z = \frac{p_{1} - p_{2}}{\sqrt{pq(\frac{1}{n_{1} }+\frac{1}{n_{2} }) } } }$

where $p = \frac{n_{1}p_{1} + n_{1}p_{2}}{n_{1}+n_{2}} = \frac{634(0.580)+567(0.229)}{634+567}$

p = 0.414

and q = 1-p = 1- 0.414 =0.586

$Z = \frac{0.580-0.229}{\sqrt{0.414(0.586)(\frac{1}{634} +\frac{1}{567} } } }$

on calculation , we get

z = 0.300 ><1.96 at 95 % level of significance

H0 is accepted

there is no difference between the proportions of Indian and Asian young people who listen to rap every day.

3 0

2 years ago

Express the confidence interval 0.555 less than 0.777 in the form Modifying above p with caret plus or minus Upper E.

Elina [12.6K]

Complete Question

Express the confidence interval 0.555 less than p less than 0.777 in the form Modifying above p with caret plus or minus Upper E.

Answer:

The modified representation is $\r p \pm E = 0.666 \pm 0.111$

Step-by-step explanation:

From the question we are told that

The confidence interval interval is $0.555 < p < 0.777$

Now looking at the values that make up the up confidence interval we see that this is a symmetric confidence interval(This because the interval covers 95% of the area under the normal curve which mean that the probability of a value falling outside the interval is 0.05 which is divided into two , the first half on the left -tail and the second half on the right tail as shown on the figure in the first uploaded image(reference - Yale University ) ) which means

Now since the confidence interval is symmetric , we can obtain the sample proportion as follows

$\r p = \frac{0.555 + 0.777}{2}$