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2 years ago

Question 4

Mathematics

1 answer:

stealth61 [152]2 years ago

3 0

Question 4:
2x-3
Because we don’t know how much Fernando has that would be where we fill in the variable giving you 2x then 3 dollars less will give you the -3 therefore 2x-3
Question 5:
1/2x+7
Because we don’t know Deb’s age that would be the variable and we are looking for half of Deb’s age giving you 1/2x then the 7 years more giving you the +7 hence 1/2x+7

You might be interested in

Solve the equation -3k+6=15

Assoli18 [71]

Answer:

K= -3

Step-by-step explanation:

-3k+6=15

-6 -6

-3k=9

/-3 /-3

k=-3

subtract 6 from both sides.

divide each side by -3 to get K alone

-3 is your answer.

8 0

2 years ago

The authors of a paper describe an experiment to evaluate the effect of using a cell phone on reaction time. Subjects were asked

Serggg [28]

Answer:

a) The 99% confidence interval would be given by (24.409;24.979)

b) n=464

Step-by-step explanation:

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".

Part a

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

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

$df=n-1=47-1=46$

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(0.025,46)".And we see that $t_{\alpha/2}=2.01$

Now we have everything in order to replace into formula (1):

$525-2.01\frac{75}{\sqrt{47}}=503.01$

$525+2.01\frac{75}{\sqrt{47}}=546.99$

So on this case the 95% confidence interval would be given by (503.01;546.99)

Part b

The margin of error is given by this formula:

$ME=t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

And on this case we have that ME =7 msec, we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{t_{\alpha/2} s}{ME})^2$ (2)

The critical value for 95% of confidence interval is provided, $t_{\alpha/2}=2.01$ from part a, replacing into formula (2) we got:

$n=(\frac{2.01(75)}{7})^2 =463.79 \approx 464$

So the answer for this case would be n=464 rounded up to the nearest integer

8 0

3 years ago

4x ≥ 12 What does it mean?

Pepsi [2]

Answer:

X = 3 or higher

Step-by-step explanation:

hope it helps, let me know if it doesn't :)

5 0

2 years ago

Read 2 more answers

One side of a rectangle is 20 cm larger than the other side. If you make the smaller side two times larger and the larger side t

grandymaker [24]

Let L be the length
Let w be the width
Let p be the perimeter
L+w+L+w=p
L=w+20
3L+2w+3L+2w=240
Sub the first equation in for L in the second equation and solve for w
3(w+20)+2w+3(w+20)+2w=240
3w+60+2w+3w+60+2w=240
10w+120=240
10w=240-120
10w=120
W=120/10
W=12
Sub w into the first equation and solve for L
L=w+20
L=12+20
L=32
Hope this helps!

3 0

3 years ago

The pie chart shows the favourite lesson of a group of students.

anastassius [24]

Answer:

Step-by-step explanation:

hope that helped

3 0

2 years ago