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3 years ago

in a chemistry class, the ratio of girls to boys is 2 to 1. if there are 30 students in the class how many girls are there

1 answer:

5 0

Firstly, we can simplify the ratio of boys to girls to
1
:
2
.
Then, to find out how many students each ratio represents, we add up
1 and 2 to get 3
(1+2=3)
By dividing 3
by the number of students, we can find how many students ONE ratio represents:
24 3=8

So ONE ratio is equal to 8
boys. Since our simplified ratio of boys to girls is
1:2
already, we do not have to do further multiplying - the number of boys is simply 8.
For the girls, simply multiply 2 by 8 to get 16

Check: 8 boys + 18 girls = 24students

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Suppose a simple random sample of size 50 is selected from a population with σ=10σ=10. Find the value of the standard error of t

bogdanovich [222]

Answer:

a) $\sigma_{\bar x} = 1.414$

b) $\sigma_{\bar x} = 1.414$

c) $\sigma_{\bar x} = 1.414$

d) $\sigma _{\bar x} = 1.343$

Step-by-step explanation:

Given that:

The random sample is of size 50 i.e the population standard deviation =10

Size of the sample n = 50

a) The population size is infinite;

The standard error is determined as:

$\sigma_{\bar x} = \dfrac{\sigma}{\sqrt{n}}$

$\sigma_{\bar x} = \dfrac{10}{\sqrt{50}}$

$\sigma_{\bar x} = 1.414$

b) When the population size N= 50000

n/N = 50/50000 = 0.001 < 0.05

Thus ; the finite population of the standard error is not applicable in this scenario;

Therefore;

The standard error is determined as:

$\sigma_{\bar x} = \dfrac{\sigma}{\sqrt{n}}$

$\sigma_{\bar x} = \dfrac{10}{\sqrt{50}}$

$\sigma_{\bar x} = 1.414$

c) When the population size N= 5000

n/N = 50/5000 = 0.01 < 0.05

Thus ; the finite population of the standard error is not applicable in this scenario;

Therefore;

The standard error is determined as:

$\sigma_{\bar x} = \dfrac{\sigma}{\sqrt{n}}$

$\sigma_{\bar x} = \dfrac{10}{\sqrt{50}}$

$\sigma_{\bar x} = 1.414$

d) When the population size N= 500

n/N = 50/500 = 0.1 > 0.05

So; the finite population of the standard error is applicable in this scenario;

Therefore;

The standard error is determined as:

$\sigma _{\bar x} = \sqrt{\dfrac{N-n}{N-1} }\dfrac{\sigma}{\sqrt{n} } }$

$\sigma _{\bar x} = \sqrt{\dfrac{500-50}{500-1} }\dfrac{10}{\sqrt{50} } }$

$\sigma _{\bar x} = 1.343$

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3 years ago

What is the height h of the parallelogram? Not drawn to scale.<br><br> Not drawn to scale.

vredina [299]

Answer:

well just from looking at the problem i would say B. 35

Step-by-step explanation:

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3 years ago

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An insurance office has 65 employees. If 39 of the employees have cellular phones, what portion of the employees do not have ce

Vsevolod [243]

65-39=26 so 26 employess dont have cellular phones. So 26/65 or in simplified form 2/5

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3 years ago

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Which of the following is most likely to bra relative maximum for this graph?

Inessa [10]

Answer:

(-1,8)

Step-by-step explanation:

Look at the top point of the parabola type thing. I know that it's not a parabola, but IDRK how else to describe it. If you see the top point at one of the answers, it is most likely correct.

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3 years ago

If you get a sneak peak at the salary list of your job and realize you are in the lowest bracket, which is the lowest 1%, what i

hoa [83]

Answer:

$z=-2.33$

And if we solve for a we got

$a=48000 -2.33*5500=35185$

And for this case the answer would be 35185 the lowest 1% for the salary

Step-by-step explanation:

Let X the random variable that represent the salary, and for this case we can assume that the distribution for X is given by:

$X \sim N(48000,5500)$

Where $\mu=48000$ and $\sigma=5500$

And we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.99$ (a)

$P(X$ (b)

We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.01 of the area on the left and 0.99 of the area on the right it's z=-2.33. On this case P(Z<-2.33)=0.01 and P(z>-2.33)=0.99

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=-2.33$

And if we solve for a we got

$a=48000 -2.33*5500=35185$

And for this case the answer would be 35185 the lowest 1% for the salary

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3 years ago

in a chemistry class, the ratio of girls to boys is 2 to 1. if there are 30 students in the class how many girls are there​

in a chemistry class, the ratio of girls to boys is 2 to 1. if there are 30 students in the class how many girls are there