Plss help??????????????

2. The National Safety Council routinely analyzes the benefit of seat belt use on driver safety. Their data showed that among 28

JulijaS [17]

Answer:

We conclude that there is difference in the proportion of deaths between the 2 groups.

Step-by-step explanation:

We are given that among 2823 drivers not wearing seat belts, 31 died as a result of injuries, and among 7765 drivers wearing seat belts 16 were killed.

Let $p_1$ = proportion of deaths when drivers were not wearing seat belts.

$p_2$ = proportion of deaths when drivers were wearing seat belts.

So, Null Hypothesis, $H_0$ : $p_1=p_2$ {means that there is no difference in the proportion of deaths between the 2 groups}

Alternate Hypothesis, $H_A$ : $p_1\neq p_2$ {means that there is difference in the proportion of deaths between the 2 groups}

The test statistics that would be used here Two-sample z test for proportions;

T.S. = $\frac{(\hat p_1-\hat p_2)-(p_1-p_2)}{\sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2} } }$ ~ N(0,1)

where, $\hat p_1$ = sample proportion of deaths when drivers were not wearing seat belts = $\frac{31}{2823}$ = 0.011

$\hat p_2$ = sample proportion of deaths when drivers were wearing seat belts = $\frac{16}{7765}$ = 0.002

$n_1$ = sample of drivers not wearing seat belts = 2823

$n_2$ = sample of drivers wearing seat belts = 7765

So, the test statistics = $\frac{(0.011-0.002)-(0)}{\sqrt{\frac{0.011(1-0.011)}{2823}+\frac{0.002(1-0.002)}{7765} } }$

= 4.438

The value of z test statistics is 4.438.

Now, at 5% significance level the z table gives critical values of -1.96 and 1.96 for two-tailed test.

Since our test statistic doesn't lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that there is difference in the proportion of deaths between the 2 groups.

Also, Margin of error (E) = $1.96 \times \sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2} }$

= $1.96 \times \sqrt{\frac{0.011(1-0.011)}{2823}+\frac{0.002(1-0.002)}{7765} }$

= 0.00397

5 0

3 years ago

Estimate the sum of 1,256, 379 and 305,986 by first rounding each number to the nearest ten thousand.

KatRina [158]

9514 1404 393

Answer:

1,570,000

Step-by-step explanation:

The sum is approximately ...

1,260,000 +310,000 = 1,570,000

_____

Additional comment

It is a good idea to estimate the error associated with an estimate. Here, both numbers are rounded up by about 4000 each, so the estimate is around 8000 high.

3 0

3 years ago

I need to know how to do the answer and why that’s the anwer

Pavel [41]

Ok so the answer is
$4 {x}^{2}$

so we multiply numbers that have the same variable

$2 {x}^{3} \: \: \times {2x}^{ - 1} \\ \\$
multiply 2 x 2

$2 \times 2 = 4$
then multiply the exponents

$x ^{3} \times x ^{ - 1}$
multipling like this will look like addition.
${x}^{3} \times {x}^{ - 1} = {x}^{2}$
so in other words you could do it like this too
${x}^{3} + {x}^{ - 1} = {x}^{2}$
now add the exponent with 4
$4 + {x}^{2} = 4x ^{2}$

now for the last part
${y}^{3} + {y}^{ - 3} = 0$
because -3 and 3 added together make 0
$0 + 4 {x}^{2} = 4 {x}^{2}$
I hope this help(it looks complicated but it's very easy and I hope I helped you out)

6 0

3 years ago

YA

True [87]

Answer:

I don't understand the question, please be more descriptive

7 0

3 years ago

Read 2 more answers

sharita does special typing jobs for scientist. she charges 16$ for the first 3 pages and 3$ for each additional page of scienti

liq [111]

Answer: 33 pages

Step-by-step explanation:

Let x represent the total number of pages typed by Sharita.

The cost of the first 3 pages = $ 16

Each additional page cost $3

Total amount paid = $106

since the first 3 pages cost $16 , and x represent the total pages , then the remaining pages will be x - 3

Also , since each additional page cost $3 , the cost of the remaining pages will be 3 ( x - 3)

Combining this , we have

16 + 3 ( x -3 ) = 106

16 + 3x - 9 = 106

7 + 3x = 106

3x = 106 - 7

3x = 99

x = 33

therefore ,Sonia's paper was 33 pages long

6 0

3 years ago