All Answers

+118725

kimhorrill:
How do I calculate a Zobt?

z = (score - mean) / stardard deviation

http://en.wikipedia.org/wiki/Standard_score

MelodyDec 19, 2013

+118725

Guest:
Problem #48:
In the August 2005 issue of Consumer Reports, readers suffering from depression reported that alternative treatments were less effective than prescription drugs. Suppose that 550 readers felt better taking prescription drugs, 220 felt better through meditation, and 45 felt better taking St. John's wort. Furthermore, 95 felt better using prescription drugs and meditation, 17 felt better using prescription drugs and St. John's wort, 35 felt better using meditation and St. John's wort, 15 improved using all three treatments, and 150 improved using none of these treatments. (Hypothetical results are partly based on percentages given in Consumer Reports.)

How many readers suffering from depression were included in the report? Of those included in the report.
b.How many felt better using prescription drugs or mediation?
c. How many felt better using St. John's wort only?
d. How many improved using prescription drugs and meditation, but not St. John's wort?
e. How many improved using prescription drugs or St. John's wort, but not meditation?
f. How many improved using exactly two of these treatments?
g.How many improved using at least one of these treatments?

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The question is a little bit ambiguous but I think that this is what it means
"220 felt better through meditation" includes all people who felt better who had used meditation, they may have used prescription drugs and/or St John's wart as well, that is not important.
It also tell us nothing about how many people used meditation and did not feel better. I have defined the other statements in a similar way.

So now what you start with is 3 overlapping circles. In the parts that don't overlap, write, presciptions, meditation and St John's wort respectively.
Now just start putting the numbers in starting in the very middle.
15 people felt better after using all 3.
now.
35 people felt better after using meditation and St john's wort. that goes in the correct overlap, but wait, there are already 3 in their. 35-3=32 so 32 goes in the other bit of the overlap.
And so on.
just keep subtracting and putting answers in the correct spots.
oh, 150 improved using none of these.
You will have to put the 3 circles inside a big rectangle and put 150 outside the circles but in the rectangle.

What you are drawing is called a Venn diagram (My brother's name is Ven so it was easy for me to remember.) It is a very useful tool for these types of question.

Now, if you have drawn it properly you should be able to work out the answers from the diagram.
Get back to me and let me know how you go.

MelodyDec 19, 2013

+118725

gamrgrrl156:
Amado and Hunter are trying to save $600 for a summer trip. Hunter started with $150 and gets $7.50 per hour working at a grocery store. Amado started with nothing but gets $12 per hour painting houses.
Make a conjecture about who will take longer to save enough money for the trip. Justify your reasoning.
Write and solve 2 equations to check your conjecture.

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Have you thought about this problem.
I can help you best if you show me what you have already tried for your self.

MelodyDec 19, 2013

+118725

Marshall:
DavidQD:
A "wide screen" TV has an aspect ratio of 16:9. find the length of a diagonal on a wide screen TV screen that has the same height as the screen from my previous question.

Reply -----

Use the height found from the previous equation then rearrange the equation to solve for D.
........
This is the rearrangement:
D = Height / SQR((H²)/(W²+H²))

If you don't mind, post your answer. The feed back is helpful in determining whether we (the tutors) are helpful and efficient, and not just responding to trolls and snarks.

--D--

-------------------------------------------------------------------------------
Thanks but my teacher unassigned it so im good! I'm not a troll and i really appreciate the help!

MelodyDec 19, 2013

+118725

Ali al Qadhi:
Sqrt3( 6x-5) +2=-3

Do you mean (Sqrt3)( 6x-5) +2=-3 Which is what you have written
or do you mean

Sqrt[3( 6x-5)] +2=-3
or
do you mean something else?

MelodyDec 19, 2013

+118725

Are you allowed to use a calculator?
If not you will have to change your mixed numberals to improper fractions first.
You try doing that and then get back to me.

MelodyDec 19, 2013

+118725

emcphee:
An astronaut observes two cities that are 46km apart, the angles between the lines of sight is 11.8 regress. Given that he is the same distance from each, hoe high above the surface of the earth is he? Ignore the earth's&w curvature

Please tell me what you have done or tried already?

MelodyDec 19, 2013

+118725

Sunshine2:
how does x=8?

from the equation 5^(4-x)=1/625

Hi Sunshine,
You must be a clever year 7 to be getting questions like this already.

(x ^-a) /1 = 1/ (x ^+a)
or alternatively
1/ (x ^-a) = (x ^+a) /1

If you write these as upright fractions you will see more clearly what I am trying to say.
Basically if something is raised to a negative power, you can get rid of the negative power by swapping the thing it belongs to, to the other side of the fraction line.
so
4 ^-2=1/(4 ²)

5 ^-3/4 = 1 / (4*5 ⁺³)

(6 * 2 ^-4) / (-7 * 3 ^-1) = (6 * 3 ⁺¹) / (-7* 2 ⁺⁴) => (6*3) / (-7*16) => 18/ (-112) => -9 / 56 Note: the -7 is not and exponent so you leave it alone.

This gets a little more complicated than your question but see if you can work out what i am trying to tell you.
I would like you to let me know if you understand or if you want it explained me simply.

MelodyDec 19, 2013

+118725

asak:
How would I go about simplifying 5^x=72? I'm very confused

You take the log of both sides. You always to this if it is an exponent (power) that you are trying to find.

then you use the log identity
log (a) ⁿ = n*log(a)
You can use any base that you please but since the calculator only deals with base 10 and base e it is usually best to choose one of those (that is assuming you want to estimate your answer.)

MelodyDec 19, 2013

+118725

Guest:
8-4i/2+2i

131219 latexcomplex numbers.JPG

MelodyDec 19, 2013

lol!

GuestDec 19, 2013

DavidQD:
A "wide screen" TV has an aspect ratio of 16:9. find the length of a diagonal on a wide screen TV screen that has the same height as the screen from my previous question.

Reply -----

Use the height found from the previous equation then rearrange the equation to solve for D.

Height= D * SQR(H²)/(W²+H²)
Width= W/H * D * SQR(H²)/(W²+H²)

Where D is the diagonal measure and
W and H are the aspect ratio expressed as W:H.

This is the rearrangement:
D = Height / SQR((H²)/(W²+H²))

If you don't mind, post your answer. The feed back is helpful in determining whether we (the tutors) are helpful and efficient, and not just responding to trolls and snarks.

--D--

Thanks but my teacher unassigned it so im good! I'm not a troll and i really appreciate the help!

GuestDec 19, 2013

Dec 18, 2013

SmartKangaroo:
Everyone knows that its 9

Thank you sooooooo much!

GuestDec 18, 2013

These circles do not touch externally, that cannot be proven.
C1: has a center at (-1, -1) and a radius of 5
C2: has a center at (7, 1) and a radius of 3

if k is a third circle where C1 and C2 touch internally, the formula would be:

(x-2.0295)^2 + (y+0.2425)^2 = (8.12)^2

GuestDec 18, 2013

+330

Stargal411:
please help, I need it in decimal form but I cant figure it out, if u can solve it, or recommend a calculator website that can solve it in decimal form, then please do, I desperately need this.