The data to represent average test scores for a class of 16 students includes an outlier value of 78. if the mean, including the outlier of 78, equals 84, which statement is always true about the new data when the outlier is removed?

Step-by-step explanation:

Given that The data to represent average test scores for a class of 16 students includes an outlier value of 78.

We can find sum of all 16 test scores = 84(16) = 1344

Outlier found = 78

If outlier is removed new sum = 1344-78 = 1266

Number of entries without outlier = 15

New average = 1266/12 =84.4

We find that average of new data increases.

Also whenever we remove outlier std deviation also would be reduced.

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