Heng tried to define a reflection across line r. Any point M not on the line of reflection maps to a point M' such that the midpoint L of M→M' is on line r.

Which counterexample shows that Heng's definition does not fully define a reflection?

Suppose there are 10 five and six-year-old attending a birthday party. when a 30 year old mother walks into the room with an infant in her arms, what happens to the mean age in the room? what happens to the standard deviation of ages in the room? a. the mean and standard deviation of both change. b. the meaning will change, but the standard deviation will stay approximately the same. c. i mean will stay approximately the same, but the standard deviation will change. d. the mean and standard deviation will both stay approximately the same.

Anyone know? will mark brainliest if you're correct!

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81