help me please !!!!!!!!!

Each side of a square is x meters long. Each side of the square is increased by 10%.

postnew [5]

Increase by 10% is time 1.10

so

area=side^2
sidenew=1.1x
so

(1.1x)^2=44 is equation

6 0

3 years ago

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The price of a sweater increased from $15 to $21. What is the percent of change

JulijaS [17]

Making some calculation the change si 25.57%

5 0

3 years ago

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

3 years ago

a football team gained 9 yards on one play and then lost 22 yards on the next. Write a sum of integers to find the overall chang

raketka [301]

$If\ they\ gained\ 9\ yards\ it\ as\ in\ our\ sum\ positive\ number\\\\If\ they\ lost\ 22\ yards\ it\ is\ negative\ number\ in\ our\ sum\\so\\9-22=-13\\\\Their\ overall\ lost\ was\ 13\ yards.\\\\Their\ position\ changed\ by\ 13\ yards\ negatively.(they\ go\ back)$

8 0

3 years ago

Need help on this math

devlian [24]

The answer should be 12 inches

5 0

2 years ago

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￼help me please !!!!!!!!!

help me please !!!!!!!!!