Answer: 
Step-by-step explanation:
Rewrite it in the form
, where 

Use Square of Sum: 

Answer:
They went over their goal for the last six months by 34 minutes per month.
Step-by-step explanation:
Mean of a data-set:
The mean of a data-set is the sum of all values in the data-set divided by the size of the data-set.
529, 499, 651, 652, 1,163, and 310 minutes on their cell phone plan.
The mean is:

By how many minutes did they go over their goal in the last six months?
The mean was of 634 minutes, and they wanted to keep it below 600. So
634 - 600 = 34
They went over their goal for the last six months by 34 minutes per month.
Amount of points don't matter what is the question lets see if I can help
n = 66
Step-by-step explanation:
you can make a proportion 3/99 = 2/x

99 * 2= 198
3 * x = 3x
so the equation would be 198 = 3x
than do 198 ÷ 3 on ur calculator
so x (or n in this context) would equal 66
Answer:
0.0545 = 5.45% probability that exactly seven are retired people.
Step-by-step explanation:
For each stock investor, there are only two possible outcomes. Either they are retired people, or they are not. Stock investors are independent. This means that we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
20% of all stock investors are retired people.
This means that 
a. What is the probability that exactly seven are retired people?


0.0545 = 5.45% probability that exactly seven are retired people.