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2 years ago

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Lucy is walking on a hill while playing with a yo-yo. She completes a trick that takes 8 seconds, and over this period of time,

the movement of the yo-yo can be represented by the expression: 1/32(x-4)^2-0.5 , , where "x" represents the number of seconds since she started the trick, and the expression represents the height of the yo-yo in meters, relative to her right hand. Over this period of time, the height of her right hand relative to sea level can be represented by the expression: -1/16(x-7)^2+12 Which of the following expressions best represents the height of the yo-yo relative to sea level over this period? *
1/32(x-11)^2+11.5
1/32(x-4)^2+1/16(x-7)^2-12.5
1/32(x-4)^2-1/16(x-7)^2+11.5

1 answer:

GenaCL600 [577]2 years ago

5 0

Answer:

1/32(x-4)^2+1/16(x-7)^2-12.5

Step-by-step explanation:

I just took my integer test LOL.

i aced it

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A random sample from a normal population is obtained, and the data are given below. Find a 90% confidence interval for . 114 157

melamori03 [73]

Answer:

$103.160 \leq \sigma \leq 187.476$

And the upper bound rounded to the nearest integer would be 187.

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 mean or variance 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.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

Data given: 114 157 203 257 284 299 305 344 378 410 421 450 478 480 512 533 545

The confidence interval for the population variance $\sigma^2$ is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^{17} (x_i -\bar x)^2}{n-1}}$

And in order to find the sample mean we just need to use this formula:

$\bar x =\frac{\sum_{i=1}^n x_i}{n}$

The sample mean obtained on this case is $\bar x= 362.941$ and the deviation s=132.250

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=17-1=16$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical values.

The excel commands would be: "=CHISQ.INV(0.05,16)" "=CHISQ.INV(0.95,16)". so for this case the critical values are:

$\chi^2_{\alpha/2}=26.296$

$\chi^2_{1- \alpha/2}=7.962$

And replacing into the formula for the interval we got:

$\frac{(16)(132.250)^2}{26.296} \leq \sigma \leq \frac{(16)(132.250)^2}{7.962}$

$10641.959 \leq \sigma^2 \leq 35147.074$

Now we just take square root on both sides of the interval and we got:

$103.160 \leq \sigma \leq 187.476$

And the upper bound rounded to the nearest integer would be 187.

4 0

2 years ago

n 2018, homes in East Baton Rouge (EBR) Parish sold for an average of $239,000. You take a random sample of homes in Ascension p

Olenka [21]

Answer:

Conclusion

There is no sufficient evidence to conclude that the mean of the home prices from Ascension parish is higher than the EBR mean

Step-by-step explanation:

From the question we are told that

The population mean for EBR is $\mu_ 1 = \$239,000$

The sample mean for Ascension parish is $\= x_2 = \$246,000$

The p-value is $p-value = 0.045$

The level of significance is $\alpha = 0.01$

The null hypothesis is $H_o : \mu_2 = \mu_1$

The alternative hypothesis is $H_a : \mu_2 > \mu_1$

Here $\mu_2$ is the population mean for Ascension parish

From the data given values we see that

$p-value > \alpha$

So we fail to reject the null hypothesis

So we conclude that there is no sufficient evidence to conclude that the mean of the home prices from Ascension parish is higher than the EBR mean

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Paraphin [41]

Answer:

least to greatest are:

-2.5, -2.47, -2/5, 5, 21/4

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Answer: Systematic

Step-by-step explanation:

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Answer:

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