the sum of three and a number is added to twenty four translate into an algebraic expression then simplify

Suppose we are interested in analyzing the weights of NFL players. We know that on average, NFL players weigh 247 pounds with a

tigry1 [53]

Answer:

$SE= \frac{\sigma}{\sqrt{n}} = \frac{47}{\sqrt{30}}= 8.58$

$ME= 1.64 *\frac{\sigma}{\sqrt{n}} = 1.64*\frac{47}{\sqrt{30}}= 14.073$

$\bar X - ME = 237- 14.073 = 222.927$

$\bar X + ME = 237+ 14.073 = 251.073$

$n=(\frac{1.640(47)}{5})^2 =237.65 \approx 238$

So the answer for this case would be n=238 rounded up to the nearest integer

Null hypothesis: $\mu \geq 247$

Alternative hypothesis: $\mu$

$z=\frac{237-247}{\frac{47}{\sqrt{30}}}=-1.165$

$p_v =P(z$

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can't conclude that the true mean is lower than 247 at 10% of significance.

Step-by-step explanation:

For this case we have the following data given:

$\bar X =237$ represent the sample mean

$\sigma = 47$ represent the population deviation

$n =30$ represent the sample size selected

$\mu_0 = 247$ represent the value that we want to test.

The standard error for this case is given by:

$SE= \frac{\sigma}{\sqrt{n}} = \frac{47}{\sqrt{30}}= 8.58$

For the 90% confidence the value of the significance is given by $\alpha=1-0.9 = 0.1$ and $\alpha/2 = 0.05$ so we can find in the normal standard distribution a quantile that accumulates 0.05 of the area on each tail and we got:

$z_{\alpha/2}= 1.64$

And the margin of error would be:

$ME= 1.64 *\frac{\sigma}{\sqrt{n}} = 1.64*\frac{47}{\sqrt{30}}= 14.073$

The confidence interval for this case would be given by:

$\bar X - ME = 237- 14.073 = 222.927$

$\bar X + ME = 237+ 14.073 = 251.073$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =5 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

Replacing into formula (b) we got:

$n=(\frac{1.640(47)}{5})^2 =237.65 \approx 238$

So the answer for this case would be n=238 rounded up to the nearest integer

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is lower than 247 pounds, the system of hypothesis would be:

Null hypothesis: $\mu \geq 247$

Alternative hypothesis: $\mu$

Since we know the population deviation, is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{237-247}{\frac{47}{\sqrt{30}}}=-1.165$

P-value

Since is a left tailed test the p value would be:

$p_v =P(z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can't conclude that the true mean is lower than 247 at 10% of significance.

5 0

2 years ago

Please help ...........

viva [34]

I believe the answer is d

7 0

3 years ago

For the school play, tickets cost $9.50 for adults and $3 for kids under 12. What would be the total cost for 8 adult tickets an

saul85 [17]

Answer:

$139
9.5aa +3kk

Step-by-step explanation:

8 adult tickets cost 8($9.50) = $76

21 kids tickets cost 21($3) = $63

The total cost of these tickets is $76 +63 = $139.

__

aa adult tickets cost 9.50aa

kk kids tickets cost 3.00kk

The total cost of these tickets is 9.50aa +3.00kk.

_____

<em>Additional comment</em>

We ordinarily expect a variable to be a single letter. This problem statement defines each variable using a double letter, so that is what we have used. (Sometimes Brainly doubles up variable content in copied text, so we suspect that may have happened here.)

4 0

2 years ago

armand deposited $389.42 in a savings account that earns 3.2% simple interest. what is armand’s account balance after 7 years?

butalik [34]

Okay so since we have $389.42 to start with, we will multiply that by 3.2% which gives us roughly $12.46. Knowing that he will get an additional $12.46 per year, we multiply 12.46 by 7, giving us $87.22. Now, we just add 87.22 to 389.42, which is 476.64. Therefore, Armand has $476.64 as his account after 7 years.

7 0

3 years ago

I got this far in my working out and am already stuck. have i gone wrong?

Kipish [7]

Yes, you made an algebraic error. By multiplying 18 x 4, you messed up on order of operations.

(x+9)(x+2)*4

becomes:

(x^2+11x+18)*4

= 4x^2 + 44x + 72

anyway, this is how I would do this problem:

(x+9)(x+2)(4) = 912

(x+9)(x+2) = 228

x^2 + 11x + 18 = 228

x^2 + 11x - 220 = 0

(x+21)(x-10) = 0

x = -21 or 10

The dimensions can't be negative, so we only use x = 10

The dimensions are then 10+9, 10+2, 4

or 19, 12, 4

6 0

3 years ago