Suppose we have collected exams scores for a statistics exam. Students are randomly assigned to one of two groups. Group 1 was to learn all of the material via in-person lectures and materials. Group 2 was to learn all of the material via online videos and materials. Researchers are interested in testing against the null hypothesis that there is no difference in population mean exam scores between the two delivery methods. There are the summary statistics after collecting data. Note that the sample sizes differ, because some subjects did not follow instructions correctly and so they were not included in the analysis. x1= 71.2, x2= 62.5
s1= 10.82, s2= 13.61
n1= 41, n2= 55

Required:
Is this an experimental or observational study?

yes

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step-by-step explanation:

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1