The National Assessment of Educational Progress (NAEP) gave a test of basic arithmetic and the ability to apply it in everyday l
1 answer:
Answer:
a) 2.0702
b) 2.07
Step-by-step explanation:
Given:
Sample, n = 840
standard deviation, σ = 60
a) The standard deviation of the sampling distribution, will be:
= 2.0702
Standard deviation of the sampling distribution is 2.0702
b) According to the 68 part of the 68-95-99.7 rule, 68% of all values of x fall within 1 standard deviation on either side of the unknown mean μ.
Therefore, missing number will be:
= 1 * 2.0702
= 2.0702 ≈ 2.07
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Asked and answered elsewhere.
brainly.com/question/9247314
You obviously don't mind using "technology" (Brainly) to answer these questions. A graphing calculator can do quadratic regression on the sequence and tell you its formula.
If you want to do it by hand, you can write the equation
.. y = ax^2 +bx +c
and substitute three of the given points. Then solve the resulting three linear equations for a, b, and c.
.. 4 = a +b +c
.. 7 = 4a +2b +c
.. 12 = 9a +3b +c
Subtracting the first equation from the other two reduces this to
.. 3 = 3a +b
.. 8 = 8a +2b
The latter can be divided by 2, so reduces to
.. 4 = 4a +b
Subtracting the first of the reduced equations from this, you have
.. 1 = a
so
.. 3 = 3*1 +b
.. 0 = b
and
.. 4 = a + b + c = 1 + 0 + c
.. 3 = c
And your equation is
.. y = x^2 +3 . . . . . . as shown previously
brainly.com/question/9247314
You obviously don't mind using "technology" (Brainly) to answer these questions. A graphing calculator can do quadratic regression on the sequence and tell you its formula.
If you want to do it by hand, you can write the equation
.. y = ax^2 +bx +c
and substitute three of the given points. Then solve the resulting three linear equations for a, b, and c.
.. 4 = a +b +c
.. 7 = 4a +2b +c
.. 12 = 9a +3b +c
Subtracting the first equation from the other two reduces this to
.. 3 = 3a +b
.. 8 = 8a +2b
The latter can be divided by 2, so reduces to
.. 4 = 4a +b
Subtracting the first of the reduced equations from this, you have
.. 1 = a
so
.. 3 = 3*1 +b
.. 0 = b
and
.. 4 = a + b + c = 1 + 0 + c
.. 3 = c
And your equation is
.. y = x^2 +3 . . . . . . as shown previously
After 1 year, the initial investment increases by 7%, i.e. multiplied by 1.07. So after 1 year the investment has a value of $800 × 1.07 = $856.
After another year, that amount increases again by 7% to $856 × 1.07 = $915.92.
And so on. After t years, the investment would have a value of .
We want the find the number of years n such that
Solve for n :