Answer:
There is sufficient evidence to support the claim that the standard deviation is less than 14.7.
Step-by-step explanation:
From the question we are told that that the null hypothesis is

Now given from the question that this null hypothesis was rejected, it mean, in non technical term that there is sufficient evidence to support the claim that the standard deviation is less than 14.7.
For problem 2, you are correct in stating that a curve forms. Specifically, if we were to trace along the outer edge of the shape, then we'd form a <u>parabola</u> that has been tilted 45 degrees compared to the more familiar form that students are taught (where the axis of symmetry is vertical).
For more information, search out "Tangent method for parabolas". As the name implies, the tangent method draws out the tangents of the parabola which helps form the parabola itself.
Everything else on your paper is correct. You have problem 1 correct, and the table is filled out perfectly. Nice work.
You would need to change the slope to -6 because perpendicular lines have opposite reciprocal slopes.
(n-3) 2n+6)
18n2-45n+25
8n-18n2-45n+25
8n-18n2
8-45n=37
37+25=62