Question

QUESTION 19 10 points Save Anawer Supp e that more than adecade ago high levels of lead in the blood put67%of til lead from the environment Suppose, In a random sample of 200 children taken more than a decade ago, what is the Oa 0.104 Ob.0.284 Oc 0.460 Od.1.000 Oe 0.000 at risk. A concerted effort was made to remove according to a survey, only 14% of children in the United States are at risk of high blood lead levels e probability that 120 or more had high blood-lead levels? QUESTION 20 10 points Save Anewer Assuming that the heights of college women are normally distributed with mean 65 inches and standard daviation 3.5 inches, what percentage of women are shorter than 68.5 inches? O 84.1% Ob,99.9% Oc. 15.9% 0 d. 50.0% 06,0.1% Cick Sove and Sabmic e and submit, Cick Save All Areers to e al ansuers Save and Submit 8 6 4

Answer 1

19)

population proportion ,p=   0.14                      
n=   200                      
                          
std error , SE = √( p(1-p)/n ) =    0.0245                      
                          
sample proportion , p̂ =   120/200=0.60   
Z=( p̂ - p )/SE= ( 0.60 -   0.14   ) /    0.0245   =   18.748
P ( p̂ >    0.6   ) =P(Z > ( p̂ - p )/SE) =                  
                          
=P(Z >   18.748   ) =    0.0000(answer)

  
excel formula for probability from z score is =NORMSDIST(Z)      

20)

µ =    65              
σ =    3.5              
left tailed                  
P( X ≤    68.5   )          
                  
Z =(X - µ ) / σ = (   68.5   -   65   ) /    3.5
Z =    1.000              
P(X ≤   68.5   ) = P(Z ≤   1.000   ) =   0.84134 or 84.1%(answer)

excel formula for probability from z score is =NORMSDIST(Z)