Answer:
The 98% confidence interval for the mean purchases of all customers is ($37.40, $61.74).
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find M as such
In which 
is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the mean subtracted by M. So it is 49.57 - 12.17 = $37.40.
The upper end of the interval is the mean added to M. So it is 49.57 + 12.17 = $61.74.
The 98% confidence interval for the mean purchases of all customers is ($37.40, $61.74).
Answer:
B) A random sample may represent the population <em>is your best answer.</em>
Step-by-step explanation:
Note that the answer choice says "may", which means that it doesn't <em>always</em> represent the population. Random samples means that they ask random people, and do not have a certain rule that they have to follow (such as recipients can only be a certain race, age, etc.) and that they can ask anybody they meet. This can give not only a higher chance of a general population's opinion, but also makes sure that there is not a high chance of obtaining misleading information.
For example, a random survey would not take place at a rally, in which most of the people would believe the same thing, and would answer fairly the same for the survey. Instead, a random survey may be taken at a busy intersection during the time when most people are out. You must note that though it has the best chance of getting a <em>more accurate</em> representation, it still isn't the most accurate. For the best accuracy, <em>everyone would have to answer the survey in which the survey question would affect</em>.
~
To do this multiply 1 by 4, then 3 by 5. 4 over 15 is your answer.
Let the number of miles be x.
Then, x miles cost 0.6x.
The initial fixed fee is $5, and the toll is $5.
cost = initial fixed fee + cost per mile + toll
46 = 5 + 0.6x + 5
0.6x + 10 = 46
0.6x = 36
x = 36/0.6
x = 60
You can travel 60 miles.
Let's factor x^2−22x+121
The middle number is -22 and the last number is 121. Factoring means we want something like
(x+_)(x+_)
Which numbers go in the blanks? We need two numbers that...
Add together to get -22
Multiply together to get 121
Can you think of the two numbers?
Try -11 and -11:
-11+-11 = -22
-11*-11 = 121
Fill in the blanks in
(x+_)(x+_)
with -11 and -11 to get...
(x-11)(x-11)
Answer: (x-11)(x-11)
Hope this helps!!!
