Do you have answer choices ??????
Answer:
Step-by-step explanation:
this system doesnt have any solutions
if you multiply the first equation by 2 you will get
2x-6y=14
second equation is
2x-6y=12
the result will -12=14
no solutions
Answer:
Step-by-step explanation:
Given that;
Compressed Soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16
Intermediate Soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26
Compressed soil intermediate soil
Mean 2.907 3.286
SD 0.1414 0.2377
Here we have,
![\bar x_1 =3.286\\ \bar x_2 =2.907\\s_1 =0.2377\\ s_2 =0.1414\\n_1=19\\n_2=20](https://tex.z-dn.net/?f=%5Cbar%20x_1%20%3D3.286%5C%5C%20%5Cbar%20x_2%20%3D2.907%5C%5Cs_1%20%3D0.2377%5C%5C%20s_2%20%3D0.1414%5C%5Cn_1%3D19%5C%5Cn_2%3D20)
The pooled Standard deviation
![s_p=\sqrt{\frac{(n_1-1)s_1^2(n_2-1)s_2^2}{n_1+n_2-2} } \\\\=0.1943](https://tex.z-dn.net/?f=s_p%3D%5Csqrt%7B%5Cfrac%7B%28n_1-1%29s_1%5E2%28n_2-1%29s_2%5E2%7D%7Bn_1%2Bn_2-2%7D%20%7D%20%5C%5C%5C%5C%3D0.1943)
So standard error for difference in population mean is
![s_{\bar x_1 - \bar x_2} = \sqrt{\frac{s_p^2}{n_1}+\frac{s_p^2}{n_2} } \\\\=0.0623](https://tex.z-dn.net/?f=s_%7B%5Cbar%20x_1%20-%20%5Cbar%20x_2%7D%20%3D%20%5Csqrt%7B%5Cfrac%7Bs_p%5E2%7D%7Bn_1%7D%2B%5Cfrac%7Bs_p%5E2%7D%7Bn_2%7D%20%20%7D%20%5C%5C%5C%5C%3D0.0623)
by inputting the values we get 0.0623
Degree of freedom for t is
df = 19 + 20 - 2 = 37,
so t-critical value is 2.715.
So required confidence interval for
will be
![( \bar x_1 - \bar x_2) \pm t_{critical}*s_{\bar x_1 - \bar x_2}](https://tex.z-dn.net/?f=%28%20%5Cbar%20x_1%20-%20%5Cbar%20x_2%29%20%5Cpm%20t_%7Bcritical%7D%2As_%7B%5Cbar%20x_1%20-%20%5Cbar%20x_2%7D)
![=0.3793 \pm2.715*0.063\\\\=0.3793\pm0.1690](https://tex.z-dn.net/?f=%3D0.3793%20%5Cpm2.715%2A0.063%5C%5C%5C%5C%3D0.3793%5Cpm0.1690)
So required confidence interval is (0.2103 , 0.5483).
No 3: he had to subtract the discount since its a discount and add on the sales tax afterwards
Answer:
B.
Step-by-step explanation:
21 X 2 = 42
42-7 = 35
35 + 21 = 56