Answer:
Step-by-step explanation:
The mean SAT score is
, we are going to call it \mu since it's the "true" mean
The standard deviation (we are going to call it
) is
![\sigma=48](https://tex.z-dn.net/?f=%5Csigma%3D48)
Next they draw a random sample of n=70 students, and they got a mean score (denoted by
) of ![\bar x=613](https://tex.z-dn.net/?f=%5Cbar%20x%3D613)
The test then boils down to the question if the score of 613 obtained by the students in the sample is statistically bigger that the "true" mean of 600.
- So the Null Hypothesis ![H_0:\bar x \geq \mu](https://tex.z-dn.net/?f=H_0%3A%5Cbar%20x%20%5Cgeq%20%5Cmu)
- The alternative would be then the opposite ![H_0:\bar x < \mu](https://tex.z-dn.net/?f=H_0%3A%5Cbar%20x%20%3C%20%5Cmu)
The test statistic for this type of test takes the form
![t=\frac{| \mu -\bar x |} {\sigma/\sqrt{n}}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B%7C%20%5Cmu%20-%5Cbar%20x%20%7C%7D%20%7B%5Csigma%2F%5Csqrt%7Bn%7D%7D)
and this test statistic follows a normal distribution. This last part is quite important because it will tell us where to look for the critical value. The problem ask for a 0.05 significance level. Looking at the normal distribution table, the critical value that leaves .05% in the upper tail is 1.645.
With this we can then replace the values in the test statistic and compare it to the critical value of 1.645.
![t=\frac{| \mu -\bar x |} {\sigma/\sqrt{n}}\\\\= \frac{| 600-613 |}{48/\sqrt(70}}\\\\= \frac{| 13 |}{48/8.367}\\\\= \frac{| 13 |}{5.737}\\\\=2.266\\](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B%7C%20%5Cmu%20-%5Cbar%20x%20%7C%7D%20%7B%5Csigma%2F%5Csqrt%7Bn%7D%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B%7C%20600-613%20%7C%7D%7B48%2F%5Csqrt%2870%7D%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B%7C%2013%20%7C%7D%7B48%2F8.367%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B%7C%2013%20%7C%7D%7B5.737%7D%5C%5C%5C%5C%3D2.266%5C%5C)
<h3>since 2.266>1.645 we can reject the null hypothesis.</h3>
Answer:
<em>90% confidence interval for the proportion of fans who bought food from the concession stand</em>
(0.5603,0.6529)
Step-by-step explanation:
<em>Step(i)</em>:-
<em>Given sample size 'n' =300</em>
Given data random sample of 300 attendees of a minor league baseball game, 182 said that they bought food from the concession stand.
<em>Given sample proportion </em>
<em> </em>![p^{-} = \frac{x}{n} = \frac{182}{300} =0.606](https://tex.z-dn.net/?f=p%5E%7B-%7D%20%20%3D%20%5Cfrac%7Bx%7D%7Bn%7D%20%3D%20%5Cfrac%7B182%7D%7B300%7D%20%3D0.606)
level of significance = 90% or 0.10
Z₀.₁₀ = 1.645
<em>90% confidence interval for the proportion is determined by</em>
![(p^{-} - Z_{0.10}\sqrt{\frac{p(1-p)}{n} } , p^{-} +Z_{0.10}\sqrt{\frac{p(1-p)}{n} })](https://tex.z-dn.net/?f=%28p%5E%7B-%7D%20-%20Z_%7B0.10%7D%5Csqrt%7B%5Cfrac%7Bp%281-p%29%7D%7Bn%7D%20%7D%20%20%2C%20p%5E%7B-%7D%20%2BZ_%7B0.10%7D%5Csqrt%7B%5Cfrac%7Bp%281-p%29%7D%7Bn%7D%20%7D%29)
![(0.6066 - 1.645\sqrt{\frac{0.6066(1-0.6066)}{300} } ,0.6066+1.645\sqrt{\frac{0.6066(1-0.6066)}{300} })](https://tex.z-dn.net/?f=%280.6066%20-%201.645%5Csqrt%7B%5Cfrac%7B0.6066%281-0.6066%29%7D%7B300%7D%20%7D%20%20%2C0.6066%2B1.645%5Csqrt%7B%5Cfrac%7B0.6066%281-0.6066%29%7D%7B300%7D%20%7D%29)
(0.6066 - 0.0463 ,0.6066 + 0.0463)
(0.5603,0.6529)
<u>final answer</u>:-
<em>90% confidence interval for the proportion of fans who bought food from the concession stand</em>
(0.5603,0.6529)
Answer:
1) (x + 3)(3x + 2)
2) x= +/-root6 - 1 by 5
Step-by-step explanation:
3x^2 + 11x + 6 = 0 (mid-term break)
using mid-term break
3x^2 + 9x + 2x + 6 = 0
factor out 3x from first pair and +2 from the second pair
3x(x + 3) + 2(x + 3)
factor out x+3
(x + 3)(3x + 2)
5x^2 + 2x = 1 (completing squares)
rearrange the equation
5x^2 + 2x - 1 = 0
divide both sides by 5 to cancel out the 5 of first term
5x^2/5 + 2x/5 - 1/5 = 0/5
x^2 + 2x/5 - 1/5 = 0
rearranging the equation to gain a+b=c form
x^2 + 2x/5 = 1/5
adding (1/5)^2 on both sides
x^2 + 2x/5 + (1/5)^2 = 1/5 + (1/5)^2
(x + 1/5)^2 = 1/5 + 1/25
(x + 1/5)^2 = 5 + 1 by 25
(x + 1/5)^2 = 6/25
taking square root on both sides
root(x + 1/5)^2 = +/- root(6/25)
x + 1/5 = +/- root6 /5
shifting 1/5 on the other side
x = +/- root6 /5 - 1/5
x = +/- root6 - 1 by 5
x = + root6 - 1 by 5 or x= - root6 - 1 by 5
Answer:
They will never have the same amount.
Step-by-step explanation:
Unless you use a number as a point "." then they will never have the same number. Sorry if this doesn't help you
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