a political candidate has asked you to conduct a poll to determine what percentage of people support her. if the candidate only wants a 8% margin of error at a 95% cnofidence level, what size of sample is needed

The  sample needed is  

Step-by-step explanation:

From the question we are told that

   The margin of error is  

   The confidence level is  

Given that the confidence level is  95% the level of significance is mathematically represented as

Next we obtain the critical value of   from the z-table , the value is

The reason we are obtaining critical value of     instead of     is because  

represents the area under the normal curve where the confidence level interval (   ) did not cover which include both the left and right tail while  

is just the area of one tail which what we required to calculate the margin of error

The sample size is mathematically represented as    

Here is sample proportion of people that supported her and we will assume this to be 50% =  0.5

So

to find the perimeter of the rectangle this is the expression:

x-9+x-9+3x-4+3x-4=138

if we simplify it:

8x-26=138

remember, 138 is what it all adds up to

the length is 11.5cm

the width is 57.5cm

the area is 661.25cm^2

the answers might not be correct use at own risk