Mathematics (Science & Mathematics) - 25 October 2007

ok the question is..... A random sample of 25 college students has an average test score of 81.5 with a standard deviation of 10.2. The population of test scores is known to be normally distributed. What is the 95% confidence interval for the mean test score of college students?

I know the equation to find the answer is 81.5+/-2.064 *10.2/sqrt25 but how do i get the 2.064

Thank You

2007-10-25 10:20:18 · 1 answers · asked by pickleporkedweasels 1

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What does sin^2(3x)+cos^2(3x) equal?

Does it still equal 1 or does it equal 3 or what? can you even do it?

2007-10-25 10:16:09 · 6 answers · asked by Kai 4

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Help with distance word problem?

"You commute 56 miles one way to work . The trip to work takes 10 minutes longer than the trip home. Your average speed on the trip home is 8mph faster. What is your average speed on the trip home?"

I'm having trouble figuring this one. Could anyone help me figure out how to do this?

2007-10-25 10:12:15 · 3 answers · asked by blacklabel5261 2

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calculus problem -_-?

A manufacturer finds it costs him x^2 +5x +7 dollars to produce x tons of an item. At production levels above 3 tons, he must hire additional workers, and his costs increase by 3(x-3) dollars on his total production. If the price he receives is #13 per ton regardless of how much he manufacturers and if he has a plant capacity of 10 tons, what level of output maximizes profits?

2007-10-25 10:02:56 · 2 answers · asked by wongtongsoup22 2

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How does this simplify (trig)?

[(sqrt3)+1] / 1-sqrt3

Can someone please show the steps how this becomes
(4+2sqrt3) / 1-3

I missed this problem on the test because I wasn't sure how to simplify

2007-10-25 09:49:53 · 2 answers · asked by Nicky 2

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If the reciprocal of 4 times a number is subtracted from the reciprocal of that number, the result is 1/12. Wh

2007-10-25 09:47:36 · 5 answers · asked by Anonymous

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What is the least common multiple for these given numbers: 3, 4, 18?

2007-10-25 09:45:31 · 4 answers · asked by Anonymous

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Will somebody show me how to turn this parabola equation into vertex form?

The equation is written:

y = 3(x+2)(x+3)

Here is what I did:

First I factored the equations: x^2 + 3x + 2x + 6
Then I added in the 3 to get: 3x^2 + 15x + 18
Then I got this: 3(x^2 + 5x) + 18
Then I did this: 3(x^2 + 5x + 6.25) + 18

Now I need to factor this part >> (x^2 + 5x + 6.25) << HELP!

2007-10-25 09:43:54 · 1 answers · asked by Anonymous

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lim as X approches 0 (sin9x)/(sin4x); evalute the limit.?

2007-10-25 09:39:41 · 1 answers · asked by Anonymous

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How does multiplying by a constant affect the slope of a function?

What is the x->a method and h ->0 method, which will work better?

f(x) = x^3

f(x) = x^4

f(x) = x^6

f(x) = x^n

2007-10-25 09:32:57 · 1 answers · asked by Brews 2

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Let f(x)=-x^2, g(x)=2x-5.?

find (f/g)(6)

2007-10-25 09:29:51 · 2 answers · asked by icygurl555 1

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How are sytems of equations usefull in real-life?

2007-10-25 09:17:51 · 4 answers · asked by imberkami p 1

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What is the equivalent stone to pounds?

I was watching a show on bbc they said this woman was really over weight cause she was 18 stone. what is that in pounds.

2007-10-25 09:14:56 · 4 answers · asked by Anonymous

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Investigate the properties of the graph of f(t) = sin(3x)^2 on [0,2/3Pi]?

Find the sub-intervals in which the function is increasing and decreasing.
Find the sub-intervals in which the function is concave up and down.
Find the inflection points of the function f on the interval? Your answer should be a set of entries of the form inflection_pt(x1,y1)

2007-10-25 09:11:40 · 1 answers · asked by Anonymous

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