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3 years ago

6

At Kennedy middle School, there are 239 e de students. Last year, SR + There were 197 students. What is the perc... Wange in the

eighth - Grade Enrollment? A. 17.6% increase B. 21.3% increase C. 82.4% increase D. 121% increase

1 answer:

andrey2020 [161]3 years ago

6 0

Sheeeeesh your school is hard djdjxjdjwnnwzhcb b129(858192029358((8

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A sociologist was investigating the ages of grandparents of high school students. From a random sample of 10 high school student

umka2103 [35]

Answer:

$(69.8-71.6) -2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= -8.908$

$(69.8-71.6) +2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= 5.308$

So then the confidence interval for the difference of means is given by:

$-8.908 \leq \mu_M -\mu_F \leq 5.308$

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X_{M}= 69.8$ represent the mean for the age of grandmother

$\bar X_{F}= 71.6$ represent the mean for the age of grandfather

$s_{M}= 8.38$ represent the sample deviation for the age of grandmother

$s_{F}= 6.65$ represent the sample deviation for the age of grandfather

$n_M = n_F= 10$

Solution to the problem

For this case the confidence interval is given by:

$(\bar X_{M} -\bar X_F) \pm t_{\alpha/2} \sqrt{\frac{s^2_M}{n_M} +\frac{s^2_F}{n_F}}$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n_M +n_F-2=10+10-2=18$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,18)".And we see that $t_{\alpha/2}=2.101$

And replacing we got:

$(69.8-71.6) -2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= -8.908$

$(69.8-71.6) +2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= 5.308$

So then the confidence interval for the difference of means is given by:

$-8.908 \leq \mu_M -\mu_F \leq 5.308$

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4 years ago

A skull cleaning factory cleans animal skulls of deer, buffalo and other types of animals using flesh-eating beetles. The fact

zhenek [66]

the answer is 16,500 days

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4 years ago

Can you please help me?

eduard

Answer:

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3 years ago

The gas tank of your car is 40% full. There are 8 gallons of gas in the tank. What is the capacity of the gas tank?

andreyandreev [35.5K]

Percentage by which the gas tank of the car is full = 40%
Amount of gas in the gas tank = 8 gallons
Let us assume the capacity of the gas tank = x gallons
Then
40% * x = 8
(40/100) * x = 8
4x/10 = 8
4x = 8 * 10
4x = 80
x = 80/4
= 20 gallons
So the total capacity of the gas tank of the car is 20 gallons. I hope the procedure is clear to you.

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4 years ago

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6 sweets cost 42p altogether how much do 8 sweets cost

Eddi Din [679]

The best thing to do is to find the cost of one sweet, and to do this, divide 42 by 7.
42/7= 6
Therefore, one sweet costs 6p.
To find the cost of 8 sweets, you've got to multiply 6 by 8, and this gives you 54p.
Therefore, 8 sweets cost 54p
This is basically just finding unit rate and multiplying.
<span>Hope this helps :)</span>

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3 years ago

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