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alexandr1967 [171]

4 years ago

8

I live for walks at a rate of 4 mph she lives 2 miles from the news station how long will it take her to walk home from the news

station

1 answer:

Tresset [83]4 years ago

3 0

um half hour? because at 4mph youll get 4 miles in an hour so 2 miles, is half the rate which makes it half hour

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Find the following difference 17 - 3.

DedPeter [7]

Answer:

14

Step-by-step explanation:

6 0

3 years ago

C.126<br> D.115<br> Geometry math question no Guessing and Please show work

MakcuM [25]

140 - 90 = 50

50/140 = 45/FE

FE = 140 * 45 / 50

FE = 126

Answer

C.126

4 0

4 years ago

Independent random samples from two regions in the same area gave the following chemical measurements (ppm). Assume the populati

g100num [7]

Answer:

The 90% confidence interval for the difference between means is (-161.18, 205.18).

Step-by-step explanation:

<u>Sample mean and standard deviation for Region I:</u>

<u />

$M=\dfrac{1}{12}\sum_{i=1}^{12}(438+1013+1127+737+...+1075+500+340)\\\\\\ M=\dfrac{8424}{12}=702$

$s=\sqrt{\dfrac{1}{(n-1)}\sum_{i=1}^{12}(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{11}\cdot [(438-(702))^2+(1013-(702))^2+...+(500-(702))^2+(340-(702))^2]}\\\\\\$

$s=\sqrt{\dfrac{1}{11}\cdot [(69696)+(96721)+...+(131044)]}\\\\\\s=\sqrt{\dfrac{1174834}{11}}=\sqrt{106803.1}\\\\\\s=326.8$

<u>Sample mean and standard deviation for Region II:</u>

<u />

$M=\dfrac{1}{15}\sum_{i=1}^{15}(778+464+563+...+479+710+389+826)\\\\\\ M=\dfrac{10204}{15}=680$

$s=\sqrt{\dfrac{1}{(n-1)}\sum_{i=1}^{15}(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{14}\cdot [(778-(680))^2+(464-(680))^2+...+(389-(680))^2+(826-(680))^2]}\\\\\\$

$s=\sqrt{\dfrac{1}{14}\cdot [(9551.804)+(46771.271)+...+(84836.27)+(21238.2)]}\\\\\\ s=\sqrt{\dfrac{545975.7}{14}}=\sqrt{38998}\\\\\\s=197.5$

Now, we have to calculate a 90% confidence level for the difference of means.

The degrees of freedom are:

$df=n1+n2-2=12+15-2=25$

The critical value for 25 degrees of freedom and a confidence level of 90% is t=1.708

The difference between sample means is Md=22.

$M_d=M_1-M_2=702-680=22$

The estimated standard error of the difference between means is computed using the formula:

$s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{326.8^2}{12}+\dfrac{197.5^2}{15}}\\\\\\s_{M_d}=\sqrt{8899.853+2600.417}=\sqrt{11500.27}=107.24$

The margin of error (MOE) can be calculated as:

$MOE=t\cdot s_{M_d}=1.708 \cdot 107.24=183.18$

Then, the lower and upper bounds of the confidence interval are:

$LL=M_d-t \cdot s_{M_d} = 22-183.18=-161.18\\\\UL=M_d+t \cdot s_{M_d} = 22+183.18=205.18$

The 90% confidence interval for the difference between means is (-161.18, 205.18).

3 0

4 years ago

HELP PICTURE SHOWN

Paul [167]

Answer: D. $\text{Area of square 1+Area of square 2=Area of square 3 }$

Step-by-step explanation:

Let the 'h' be the length of the hypotenuse of the right angle, 'a' be the side corresponding to the square 2 and 'b' be the side corresponding to the square 1 .

Since, area of square = $(side)^2$

Then, Area of square 1 = $b^2$ ......................(1)

Area of square 2 = $a^2$ ......................(2)

Area of square 3 = $h^2$ ......................(3)

Using Pythagoras theorem in given right triangle, we get

$h^2=a^2+b^2\\\\\Rightarrow\text{Area of square 3 =Area of square 1+Area of square 2 }$ [from (1),(2) and (3)]

6 0

3 years ago

How do you know which number in an exponential function controls how much it is stretched or compressed?

zhenek [66]

To evaluate an exponential function with the form f (x) = b x \displaystyle f\left(x\right)={b}^{x} f(x)=bx

5 0

3 years ago