Answer:
The minimum sample size needed is  . If n is a decimal number, it is rounded up to the next integer.
. If n is a decimal number, it is rounded up to the next integer.  is the standard deviation of the population.
 is the standard deviation of the population.
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:
 level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Z-table as such z has a p-value of  .
.
That is z with a pvalue of  , so Z = 1.645.
, so Z = 1.645.
Now, find the margin of error M as such

In which  is the standard deviation of the population and n is the size of the sample.
 is the standard deviation of the population and n is the size of the sample.
How large a sample must she select if she desires to be 90% confident that her estimate is within 4 ounces of the true mean?
A sample of n is needed, and n is found when M = 4. So






The minimum sample size needed is  . If n is a decimal number, it is rounded up to the next integer.
. If n is a decimal number, it is rounded up to the next integer.  is the standard deviation of the population.
 is the standard deviation of the population.
 
        
             
        
        
        
Answer:
20%
Step-by-step explanation:
150-120 is 30
30 is 1/5 of 150
1/5 is .2, which is 20%
Hope that helps~
 
        
             
        
        
        
Answer:
A. 
Step-by-step explanation:
We are given,
The cost of one book = $2.25
Since, it takes $2.25 to buy 1 book.
The, for $10, we can get  i.e.
 i.e.  = 4.44
 = 4.44
Since, number of books cannot be in decimals.
So, the closest integer to 4.44 is 4.
Hence, we can buy 4 books from $10.
Now, according to the options:
A. 
B. 
C. 
D. 
Hence, we see that from the options, A is correct.
 
        
                    
             
        
        
        
Answer:
steps below
Step-by-step explanation:
f(x) = x + 5
g(x) = x - 4
f(g(x)) = f(x-4) = (x-4) + 5
 
        
             
        
        
        
First you would divide everything by bc on both sides to get a by it self. Then you answer will be a=c/bc