a. Let
be a random variable representing the weight of a ball bearing selected at random. We're told that
, so

where
. This probability is approximately

b. Let
be a random variable representing the weight of the
-th ball that is selected, and let
be the mean of these 4 weights,

The sum of normally distributed random variables is a random variable that also follows a normal distribution,

so that

Then

c. Same as (b).
Answer: The center of the circle is 3+7i
Explanation: Let z1 and z1 be the two end points and c be the center to be determined. The center lies half of the difference between z1 and z1, measured from z1:

Answer:

Step-by-step explanation:

Add
and
on both sides.

Add or subtract like terms.

Divide
on both sides.


is the independent variable now.
Hint: Try using the Pythagorean thereom to solve it.