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Find the z-score for the standard normal distribution where: P(z<+a)=0.9625.
or the other one is: If the random variable z is a Standard Normal Score, what is P(-2.00 <_ z <_ +2.00)? How did you find this probability?
We are not suppoose to use any calulators or anything but the Cumulative Standard Normal Table Charts.
1 solutions
Answer 410323 by ewatrrr(10682) on 2012-09-28 11:24:11 (Show Source):
You can put this solution on YOUR website!
Hi,Re TY, good news is that You will not be expected to do this "long-hand"
that's why there are charts, Excel functions, calculators like the TI83, etc
to find either the z-value given the P-value or the P-value given the z-value
for ex: using Excel function: NORMSINV(.9625) = 1.7805
and P(-2.00 <_ z <_ +2.00)= NORMSDIST(2)-NORMSDIST(-2) = .9544
Important to Understand z -values as they relate to the Standard Normal curve:
Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.
Note: z = 0 , 50% of the area under the curve is to the left and 50% to the right
This particular 'chart' below shows the amount of area under the Normal distribution curve between z = 0 and the z given
(half the total area to the left of the z-value)
that is to say one would add .50 to each entry for total area under the curve to the left of the z value.
Highlighted + .50 is .9625 and P(z<+a)=0.9625, a = 1.78 (the 8 coming from the .08 column)
As to P(-2.00 <_ z <_ +2.00) = .4772 + .4772 = .9544
Z 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
0.0 0.0000 0.0040 0.0080 0.0120 0.0160 0.0199 0.0239 0.0279 0.0319 0.0359
0.1 0.0398 0.0438 0.0478 0.0517 0.0557 0.0596 0.0636 0.0675 0.0714 0.0753
0.2 0.0793 0.0832 0.0871 0.0910 0.0948 0.0987 0.1026 0.1064 0.1103 0.1141
0.3 0.1179 0.1217 0.1255 0.1293 0.1331 0.1368 0.1406 0.1443 0.1480 0.1517
0.4 0.1554 0.1591 0.1628 0.1664 0.1700 0.1736 0.1772 0.1808 0.1844 0.1879
0.5 0.1915 0.1950 0.1985 0.2019 0.2054 0.2088 0.2123 0.2157 0.2190 0.2224
0.6 0.2257 0.2291 0.2324 0.2357 0.2389 0.2422 0.2454 0.2486 0.2517 0.2549
0.7 0.2580 0.2611 0.2642 0.2673 0.2704 0.2734 0.2764 0.2794 0.2823 0.2852
0.8 0.2881 0.2910 0.2939 0.2967 0.2995 0.3023 0.3051 0.3078 0.3106 0.3133
0.9 0.3159 0.3186 0.3212 0.3238 0.3264 0.3289 0.3315 0.3340 0.3365 0.3389
1.0 0.3413 0.3438 0.3461 0.3485 0.3508 0.3531 0.3554 0.3577 0.3599 0.3621
1.1 0.3643 0.3665 0.3686 0.3708 0.3729 0.3749 0.3770 0.3790 0.3810 0.3830
1.2 0.3849 0.3869 0.3888 0.3907 0.3925 0.3944 0.3962 0.3980 0.3997 0.4015
1.3 0.4032 0.4049 0.4066 0.4082 0.4099 0.4115 0.4131 0.4147 0.4162 0.4177
1.4 0.4192 0.4207 0.4222 0.4236 0.4251 0.4265 0.4279 0.4292 0.4306 0.4319
1.5 0.4332 0.4345 0.4357 0.4370 0.4382 0.4394 0.4406 0.4418 0.4429 0.4441
1.6 0.4452 0.4463 0.4474 0.4484 0.4495 0.4505 0.4515 0.4525 0.4535 0.4545
1.7 0.4554 0.4564 0.4573 0.4582 0.4591 0.4599 0.4608 0.4616 0.4633
1.8 0.4641 0.4649 0.4656 0.4664 0.4671 0.4678 0.4686 0.4693 0.4699 0.4706
1.9 0.4713 0.4719 0.4726 0.4732 0.4738 0.4744 0.4750 0.4756 0.4761 0.4767
2.0 0.4778 0.4783 0.4788 0.4793 0.4798 0.4803 0.4808 0.4812 0.4817
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Quadratic-relations-and-conic-sections/658044: Find the equation of the ellipse with vertices (0, -1) and (12, -1) and minor axis of length 6
And:
What is the equation of the axis of symmetry of the parabola whose equation is 2(y - 2) = (x + 3)2?
x = -3
x = 3
x = 0
y = -2
y = 2 1 solutions
Answer 410129 by ewatrrr(10682) on 2012-09-27 13:25:14 (Show Source):
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Probability-and-statistics/658026: An experimental drug has been shown to be 75% effective in eliminating symptoms of allergies in animal studies. A small human study involving six participants is conducted. What is the probability that the drug is effective on more than half of the pariticpants? 1 solutions
Answer 410121 by ewatrrr(10682) on 2012-09-27 12:50:43 (Show Source):
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Probability-and-statistics/658025: In a primary care clinic, 25% of all patients who have appointments fail to show up. Each clinic sessions has 10 scheduled appointments. 1) What is the probability that half of the patients fail to show up? 2) What is the probability that all patients show up? 3) In a week, there are 10 clinic sessions. How many patients would you expect to fail to show up? 1 solutions
Answer 410116 by ewatrrr(10682) on 2012-09-27 12:41:40 (Show Source):
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Quadratic-relations-and-conic-sections/658020: Which of the following are true about the parabola with equation x2=12y? Choose all that apply:
The focus is (0,3).
The directrix is y=-3.
The focus is (0,-3).
The vertex is (0,0). 1 solutions
Answer 410107 by ewatrrr(10682) on 2012-09-27 12:18:21 (Show Source):
You can put this solution on YOUR website!
Hi,
Note: vertex form of a Parabola opening up(a>0) or down(a<0),
where(h,k) is the vertex and x = h is the Line of Symmetry
The standard form is , where the focus is (h,k + p)
, V(0,0), 4p = 12, p = 3, F(0,3) and directrix is y = -3

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Problems-with-consecutive-odd-even-integers/658012: find three consecutive odd integers whose sum is 75
2(4x-3)-8=4+2x
2/3(3x+18)=5x-9
these are two problems that I have attempted to solve but I am not sure if thery are correct
1 solutions
Answer 410100 by ewatrrr(10682) on 2012-09-27 11:51:19 (Show Source):
You can put this solution on YOUR website!
Hi,
x + (x+2) + (x+4) = 75, 3x = 69, x = 23 ||| 23, 25, 27 the 3 consecutive odd integers
"PEMDAS", "Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction".
2(4x-3)-8=4+2x
8x - 6 - 8 = 4 + 2x, 6x = 18, x = 18/6 0r x = 3
2/3(3x+18)=5x-9
2x + 12 = 5x - 3, 15 = 3x, x = 5
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