The scale factor of the dilation is 1 because the image and pre-image share the SAME everything (lengths, area, etc.). So if you multiply one of the image’s length by any number other than one, the pre-image will change.

3 0

3 years ago

A standardized exam's scores are normally distributed. In a recent year, the mean test score was 14901490 and the standard dev

kicyunya [14]

<h2>Answer with explanation:</h2>

Given : A standardized exam's scores are normally distributed.

Mean test score : $\mu=1490$

Standard deviation : $\sigma=320$

Let x be the random variable that represents the scores of students .

z-score : $z=\dfrac{x-\mu}{\sigma}$

We know that generally , z-scores lower than -1.96 or higher than 1.96 are considered unusual .

For x= 1900

$z=\dfrac{1900-1490}{320}\approx1.28$

Since it lies between -1.96 and 1.96 , thus it is not unusual.

For x= 1240

$z=\dfrac{1240-1490}{320}\approx-0.78$

Since it lies between -1.96 and 1.96 , thus it is not unusual.

For x= 2190

$z=\dfrac{2190-1490}{320}\approx2.19$

Since it is greater than 1.96 , thus it is unusual.

For x= 1240

$z=\dfrac{1370-1490}{320}\approx-0.38$

Since it lies between -1.96 and 1.96 , thus it is not unusual.

5 0

3 years ago