Answer:
Step-by-step explanation:
To simplify or to write in the form a+bi, you will need multiply the top and bottom by the bottom's conjugate like so:
Keep in mind when multiplying conjugates you only have to multiply first and last.
That is the product of (a+b) and (a-b) is (a+b)(a-b)=a^2-b^2.
(a+b) and (a-b) are conjugates
Let's multiply now:
i^2=-1
Answer:
0.0668
Step-by-step explanation:
Assuming the distribution is normally distributed with a mean of $75,
with a standard deviation of $12.
We can find the z-score of 78 using;
Using our normal distribution table, we obtain the area that corresponds to 0.25 to be 0.9332
This is the area corresponding to the probability that, the average is less or equal to 78.
Subtract from 1 to get the complement.
P(x>78)=1-0.9332=0.0668