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3 years ago

11

Which number replaces the box to make this a true number sentence? 4 × (8 – 5) = (4 × 8) – ( × 5) A. 4 B. 5 C. 12 D. 32

1 answer:

Andre45 [30]3 years ago

3 0

The answer is A: 4. This is easy once you know the order of operations, aka PEMDAS. Parentheses, exponents, multiplication/division, and addition/subtraction.

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The sugar content of the syrup in canned peaches is normally distributed. A random sample of n = 10 cans yields a sample standar

Serggg [28]

Answer:

The 95% confidence interval is given by:

3.30<σ<8.76

Step-by-step explanation:

1) Data given and notation

s=4.798 represent the sample standard deviation

$\bar x$ represent the sample mean

n=10 the sample size

Confidence=95% or 0.95

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 .

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

$df=n-1=10-1=9$

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 tabel to find the critical values.

The excel commands would be: "=CHISQ.INV(0.025,9)" "=CHISQ.INV(0.975,9)". so for this case the critical values are:

$\chi^2_{\alpha/2}=19.022$

$\chi^2_{1- \alpha/2}=2.700$

And replacing into the formula for the interval we got:

$\frac{(9)(4.798)^2}{19.022} \leq \sigma \frac{(9)(4.798)^2}{2.700}$

$10.892 \leq \sigma^2 \leq 76.736$

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

$3.30 \leq \sigma \leq 8.76$

So the best option would be:

3.30<σ<8.76

7 0

3 years ago

Find the real solution(s) by solving for x (round any decimals to the nearest 100th);<br> 5x = 320

baherus [9]

Answer:

x=64

Step-by-step explanation:

5x = 320

Divide each side by 5

5x/5 = 320/5

x=64

6 0

3 years ago

Read 2 more answers

EVALUATE THE FOLLOWING EXPRESSION <br> 6-2+4-8

Nikitich [7]

6-2+4-8 = 4+4-8 = 8-8 = 0

7 0

3 years ago

Brass is made from a mixture of copper and other elements. a mixture that is 80% copper is combined with a mixture that is 60% c

algol [13]

The equation that can be used to find x, the amount of the 60% mixture used to create the 65% mixture is:

0.60*x + 0.80*(100 - x) = 0.65*(100).

<h3>Which equation we should use?</h3>

First, let's define two variables:

x = pounds of the 60% copper brass.
y = pounds of the 80% copper brass.

We know that we want to make 100 lb of 65% copper brass, then we must have that:

x + y = 100

And the percentage of copper before and after mixing must be the same, so we can write:

0.60*x + 0.80*y = 0.65*(x + y).

(where the percentages are written in decimal form).

Then we have a system of equations:

x + y = 100

0.60*x + 0.80*y = 0.65*(x + y).

To get a single equation, we can isolate the variable "y" on the first equation:

y = 100 - x

Now we replace that in the other equation:

0.60*x + 0.80*(100 - x) = 0.65*(100).

This is what we wanted to get, an equation that can be used to find x, the amount of the 60% mixture used to create the 65% mixture.

If you want to learn more about systems of equations:

brainly.com/question/13729904

#SPJ1

4 0

2 years ago

Find m<br> A. 38<br> B. 76<br> C. 142<br> D. 71

baherus [9]

I think the answer is a. because all sides are the same.

1 side = 38

side m = probably 38

Hope this helped☺☺

8 0

3 years ago

Read 2 more answers