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Zolol [24]
3 years ago
14

Please help, I’m unsure how to do standard deviation so I’m very confused!

Mathematics
1 answer:
lidiya [134]3 years ago
6 0

a. With an average/mean of 7 dreams, one standard deviation away from the mean corresponds to the interval [7 - 1.7, 7 + 1.7] = [5.3, 8.7]. So children within one standard deviation of the mean experience somewhere between 5 and 9 dreams. Two standard deviations from the mean refers to the interval [7 - 2 * 1.7, 7 + 2 * 1.7] = [3.6, 10.4]. So children in this range have between 3.6 and 10.4 dreams.

b. We already know that the interval [5.3, 8.7] is one standard deviation from the mean. If we assume the number of dreams is normally distributed with mean 7 and standard deviation 1.7, then we can apply the empirical rule (a.k.a. 68-95-99.7), which says that for any normal distribution, roughly 68% of the distribution falls within one standard deviation of the mean. So we can expect roughly 68% of the 4800 children to have between 5.3 and 8.7 dreams, or about 3264 students.

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I need help with this.
mrs_skeptik [129]
The answer to the question. Estimated at 60,000

6 0
3 years ago
David measures how many inches his tomato plant grows every week. What is the independent variable?​
Norma-Jean [14]

Answer:

It is tomato plant

Step-by-step explanation:

- The independent variable is the variable the experimenter changes or controls and is assumed to have a direct effect on the dependent variable. - - - The dependent variable is the variable being tested and measured in an experiment, and is 'dependent' on the independent variable.

7 0
3 years ago
Find the differential equation of the family of tangent lines to the parabola y^2 = 2x
dusya [7]
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5 0
3 years ago
The sum of the digits of a two-digit number is 5. If the number is multiplied by 3, the result is 42. Write and solve a system o
Elenna [48]
A two digit number has a tens digit and a ones digit.
Let's say x = tens digit and y = ones digit

"The sum of the digits is 5"
x + y = 5

The next phrase is "the number multiplied by 3 is 42" but we need to represent the number using the digits. So they need to be multiplied first by their place value and added together. [Example: 34 = 3(10) + 4(1)]

The number is: 10x + y
3(10x + y) = 42

The system of equations: (two equations for two unknowns)
x + y = 5
30x + 3y = 42

Then you can use substitution or elimination to combine and solve.
I'll use elimination, multiply the entire top equation by -3 and add the equations together. y will cancel out

-3x - 3y = -15
30x + 3y = 42
------------------
27x + 0 = 27
x = 1

then plug x = 1 into either equation to find y

1 + y = 5
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remember the x and y represent digits so the number xy is 14
6 0
3 years ago
Can u pls help me with this question asap ​
RideAnS [48]

Answer:

90

Step-by-step explanation:

Basically 90 precent of 100 is 90

7 0
3 years ago
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