Answer:
(i) The student who weighed the rock 20 times.
Step-by-step explanation:
The margin of error of a confidence interval is:

In which z is related to the confidence level,
is the standard deviation of the population and n is the size of the sample.
From the equation above, the larger the size of the sample, the lower the margin is, that is, the narrower the interval is.
In this question:
A student weighed the rock 20 times and other the 5. From above, the one who weighed the rock 20 times will have the more precise interval.
So the correct answer is:
(i) The student who weighed the rock 20 times.

<h2>
Explanation:</h2>
The Standard Form of the equation of a parabola is given by the form:

As y is a function of x, then we can write:

Also, we can write
in factored form as:

In this case:

So:

We also know that the parabola passes through the point (1,6):

Finally, the equation of the parabola is:

Or applying Distributive Property:

<h2>Learn more:</h2>
Piecewise-defined function: brainly.com/question/12169258
#LearnWithBrainly
Answer:
5/8
Step-by-step explanation:
5/8 has the greatest value
1) 4x + 5
2) 14w2 - 4w
3) -x + 19
4) 19x - 16
5) -x2 - x
6) 11a2b - 12ab2
Answer:

Step-by-step explanation:
The equation of a parabola in vertex form:

<em>(h, k)</em><em> - vertex</em>
The focus is

We have the vertex (2, -5) and the focus (2, -4).
Calculate the value of <em>a</em> using 
<em>k = -5</em>
<em>add 5 to both sides</em>
<em>multiply both sides by 4</em>


Substitute

to the vertex form of an equation of a parabola:

The standard form:

Convert using


<em>use the distributive property: a(b+c)=ab+ac</em>
