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UkoKoshka [18]
4 years ago
13

A multiple choice test consists of 60 questions. Each question has 4 possible answers of which one is correct. If all answers ar

e random guesses, Estimate the probability of getting at least 12 correct answers. (Hint: Use the Normal Approximation to binomial).
Mathematics
1 answer:
timofeeve [1]4 years ago
4 0

Answer:

0.8508

Step-by-step explanation:

In this question, we are asked to estimate the probability of getting at least 12 correct answers.

X ~ Bin ( n , p)

Where n = 60 , p = 1/4 = 0.25

Mean = np = 60 * 0.25 = 15

Standard deviation = sqrt [ n p ( 1 - p) ] = Sqrt [ 60 * 0.25 ( 1 - 0.25) ] = 3.3541

Using normal approximation

P(X < x) = P(Z < ( x - mean) / SD )

P(X >= 12) = P(X > 11.5)

= P(Z > ( 11.5 - 15) / 3.3541 )

= P(Z > -1.04)

= P(Z < 1.04)

= 0.8508

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.Using a table of values, determine the solution to the equation below to the nearest fourth of a unit. x+4= -3^x+4
Oxana [17]
Remark
The very first thing you should do with a question like this is get the graph. Then you will know what you are looking for. I have provided you with such a graph. Your table should center around -2 ≤ x ≤ -1

So let's set up a table and see what we get. Start with y = x + 5

x             x + 5
-1           4
-1.25      3.75
-1.5        3.5
-1.75      3.25
-2           3

Do the same thing for - (3)^x + 4 See below to see how this is entered your calculator

x            -(3)^x + 4
-1           3.66
-1.25      3.75
-1.5        3.8
-1.75      3.85
-2           3.89

Conclusion
When x = - 1.25 y = 3.75 for both graphs. <<<< Answer

Footnote
You may not be familiar with how to put this in your calculator. This is the way I would do it. I'm only doing it for y = -(3^x) + 4

Let x = - 1.25
3
^ Note your calculator might have x^y or y^x. You'll have 1 of the three.
1.25
+/- 
=
X
1
+/-
=     At this point you should have -0.25
+
4
= 
That gives you 3.75



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3 years ago
a 10-foot ladder leans against a wall with its foot braced 3 feet from wall's base. how far up the wall does the ladder reach? r
andrezito [222]
Use pythagoras teorem

10^2 = 3^2 + x^2

x^2 = 100 - 9 = 91

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Answer:

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Lastly, you would have this all equaling y, as y is the total amount of pies.

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I dont not understand
mina [271]

Answer:

Step-by-step explanation:

all you HAVE TO DO IS ADD THEM ALL TOGETHER

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