Question 288143:  According to the US Census Bureau, roughly 14.5% of individuals are living below the poverty level. Suppose a random sample of 500 individuals was taken.  
a.  Describe the sampling distribution of p-hat, the sample proportion of individuals living below the poverty level.
 
        1.  The mean of p-hat is:_________
 
        2.  The standard error of p-hat is:_________
 
3.  In a random sample of 500 individuals, find the probability that no more than 10% are living below the poverty level. 
What is the probability that a random sample of 500 individuals results in 80 or more having an advanced degree? 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website!  According to the US Census Bureau, roughly 14.5% of individuals are living below the poverty level. 
Suppose a random sample of 500 individuals was taken.  
a. Describe the sampling distribution of p-hat, the sample proportion of individuals living below the poverty level.  
1. The mean of p-hat is: 14.5% according to the Central Limit Theorem 
======================== 
2. The standard error of p-hat is: sqrt(0.145*0.855/500) = 0.0157 according to CLT 
========================  
3. In a random sample of 500 individuals, find the probability that no more than 10% are living below the poverty level. 
--- 
Find the z-value that has a left tail of 10%: z = -1.2816.. 
Find the x-value associated with z = -1.2816 
x = -1.2816*0.0157+ 0.145  
x = 0.1249  
---------------------------------- 
Cheers, 
Stan H. 
 
  | 
 
  
 
 |   
 
 |