In: Statistics and Probability
A global research study found that the majority of today's working women would prefer a better work-life balance to an increased salary. One of the most important contributors to work-life balance identified by the survey was "flexibility," with 41% of women saying that having a flexible work schedule is either very important or extremely important to their career success. Suppose you select a sample of 100 working women. Answer parts (a) through (c).
If a sample of 400 is taken, how does this change your answers to (a) through (c)?
A) The probability that in the sample fewer than 47% say that having a flexible work schedule is either very important or extremely important to their career success is?
B) The probability that in the sample between 36% and 47% say that having a flexible work schedule is either very important or extremely important to their career success is?
C) The probability that in the sample more than 37% say that having a flexible work schedule is either very important or extremely important to their career success is?
a)
population proportion ,p=   0.41  
   
n=   400      
          
std error , SE = √( p(1-p)/n ) =    0.024592  
   
          
sample proportion , p̂ =   0.47  
   
Z=( p̂ - p )/SE=   2.440  
   
P ( p̂ <    0.47   ) =P(Z<( p̂ - p )/SE)
=  
          
=P(Z <    2.440   ) =   
0.9927
The probability that in the sample fewer than 47% say that having a flexible work schedule is either very important or extremely important to their career success is 0.9927
B)
          
            population
proportion ,p=   0.41      
   
          
           
n=   400      
   
          
           
           
   
          
            std error
, SE = √( p(1-p)/n ) =    0.0246  
       
          
           
           
   
          
            we need to
compute probability for       
       
          
           
0.36   < p̂ <   0.47  
   
          
           
           
   
          
            Z1 =( p̂1
- p )/SE=   -2.033      
   
          
            Z2 =( p̂2
- p )/SE=   2.440      
   
P(   0.36   < p̂ <  
0.47   ) =    P[( p̂1-p )/SE< Z
<(p̂2-p)/SE ]    =P(    -2.033  
< Z <   2.440   )
          
           
           
   
= P ( Z <   2.440   ) - P (   
-2.033   ) =    0.9927  
-   0.021   =  
0.9716  
The probability that in the sample between 36% and 47% say that
having a flexible work schedule is either very important or
extremely important to their career success is = 0.9716
-------------------------
c)
population proportion ,p=   0.41  
   
n=   400      
          
std error , SE = √( p(1-p)/n ) =    0.025  
   
          
sample proportion , p̂ =   0.37  
   
Z=( p̂ - p )/SE=   -1.627  
   
P ( p̂ >    0.37   ) =P(Z > ( p̂ - p
)/SE) =  
          
=P(Z >   -1.627   ) =   
0.9481
The probability that in the sample more than 37% say that having a flexible work schedule is either very important or extremely important to their career success is 0.9481