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KonstantinChe [14]
3 years ago
14

Suppose the salaries of university professors are approximately normally distributed with a mean of $65,000 and a standard devia

tion of $7,000. If a random sample of size 25 is taken and the mean is calculated, what is the probability that the mean value will be between $62,500 and $64,000
Mathematics
1 answer:
Kaylis [27]3 years ago
5 0

Answer:

0.2009

Step-by-step explanation:

Mean(μ) = 65000

Standard deviation (σ) = 7000

n = 25

Let X be the random variable which is a measure of salaries of university professors

Z = (μ - x) /σ/√n

Pr(62500 ≤ x ≤ 64000) = ???

Pr((65000 - 62500)/7000/√25 ≤ z ≤ (65000 - 64000) / 7000/√25)

= Pr(2500 / 7000/5 ≤ z ≤ 1000 / 7000/5)

= Pr(2500 / 1400 ≤ z ≤ 1000/1400)

= Pr(1.79 ≤ z ≤ 0.714)

= Pr(0 ≤ z ≤ 1.79) - Pr(0 ≤ z ≤ 0.714)

From the normal distribution table we have

0.4633 - 0.2624

= 0.2009

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For a school fundraiser students are selling snack bags and candy bars to raise money on Wednesday the students or 23 snack bags
meriva

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$1.75

Step-by-step explanation:

The selling for each candy bar may be determined by  a set of linear equations. This pair of linear equations may be solved simultaneously by using the elimination method. This will involve ensuring that the coefficient of one of the unknown variables is the same in both equations.

It may be solved by substitution in that one of the variable is made the subject of the equation and the result is substituted into the second equation .

Let the cost of a snack bag be s and that of a candy bar be c, then if on Wednesday the students or 23 snack bags and 36 candy bars that raised $114.75 on Thursday the seventh so 37 snack bags and 36 candy bars that raised $146.25

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Answer:

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Step-by-step explanation:

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y = 2x - 3

x + y = 18

1. Approach

The easiest way to solve this system of equations is to solve the second equation for the variable (y). Then add the systems, use algebra to solve for the value of (x), then substitute that value back into one of the original equations to solve for the value of (y). Another name for the method in use is the method of elimination, this is when a [erspm manipulates one of the equations in a system of the equation such that when they add the equations, one of the variables eliminatates. Thus, they can solve for the other variable and the backsolve for the value of the unknown variable.

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x + y = 18

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x - 18 = -y

3. Use elimination

Now substitute this back into the original system,

y = 2x - 3

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Add the systems,

y = 2x - 3

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_________

0 = 3x - 21

Inverse operations,

0 = 3x - 21

+21       +21

21 = 3x

/3    /3

7 = x

4. Find the value of the unknown variable

Backsovle to find the value of (y),

x + y = 18

Substitute,

7 + y = 18

Inverse operations,

7 + y = 18

-7        -7

y = 11

3 0
2 years ago
Read 2 more answers
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