The perimeter of a rectangle is 48 cm its length is 4 cm what is the width

Is this correct? Please help.

k0ka [10]

Answer:

I believe your answer is correct.

Step-by-step explanation:

3 0

3 years ago

83 random samples were selected from a normally distributed population and were found to have a mean of 32.1 and a standard devi

arlik [135]

Answer:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.525 \leq \sigma^2 \leq 7.602$

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

$2.127 \leq \sigma \leq 2.757$

Step-by-step explanation:

Information given

$\bar X=32.1$ represent the sample mean

$\mu$ population mean (variable of interest)

s=2.4 represent the sample standard deviation

n=83 represent the sample size

Confidence interval

The confidence interval for the population variance is given by the following formula:

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

The degrees of freedom given by:

$df=n-1=8-1=7$

The confidence level 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 table to find the critical values.

The excel commands would be: "=CHISQ.INV(0.05,82)" "=CHISQ.INV(0.95,82)". so for this case the critical values are:

$\chi^2_{\alpha/2}=104.139$

$\chi^2_{1- \alpha/2}=62.132$

The confidence interval is given by:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.525 \leq \sigma^2 \leq 7.602$

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

$2.127 \leq \sigma \leq 2.757$

5 0

3 years ago

Squared root 50 x squared root 8<br><br> surds

frez [133]

Answer:

20

Step-by-step explanation:

using the rule of radicals

$\sqrt{a}$ × $\sqrt{b}$ = $\sqrt{ab}$ , then

$\sqrt{50}$ × $\sqrt{8}$

= $\sqrt{50(8)}$

= $\sqrt{400}$

= 20

6 0

1 year ago

The product of 3 and a number is 12 more than the sum of the number and 26. What is the number?

Karo-lina-s [1.5K]

The product of three and a number (3n) is 12 more than (=12 +) the sum of the number and 26 (n + 26). Put all of those together.

2n = 12 + n + 26 Combine like terms. (12 + 26)
2n = 28 + n Subtract to get the variables together. (2n - n)
n = 28

4 0

3 years ago

For a sample of eight bears, researchers measured the distances around the bears' chests and weighed the bears. Minitab was us

Karolina [17]

Answer:

Step-by-step explanation:

Given that for a sample of eight bears, researchers measured the distances around the bears' chests and weighed the bears.

r = linear correlation coeff = 0.952

H_0: r =0\\

H_1 :r\neq 0

(Two tailed test)

r difference = 0.952

n=8

Std error = \sqrt{\frac{1-r^2}{n-2} } =0.12496

Test statistic t = 0.952/0.12496 = 7.618

Alpha = 0.05

df = 6

p value = 0.000267

This implies H0 is rejected.

There exists a linear relation between the variables and r cannot be 0

0.952^2 = 0.906=90.6% of variation in weight can be explained by the linear relationship between weight and chest size

3 0

3 years ago