Normal Distribution in Probability












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$begingroup$


I can solve the k, but I am not really able to do the rest!



The mass M of apples in grams is normally distributed with mean μ . The following table shows probabilities for values of M .
Values: M>93 -> p(x)=k
93< M < 119 -> p(x)= 0.98
119 < M -> p(x)= 0.01
Part a:
(i) Write down the value of k .
(ii) Show that μ = 106.
Part b:
Find P (M < 95) .
Part c and d:
The apples are packed in bags of ten.Any apples with a mass less than 95 g are classiied as small.



Find the probability that a bag of apples selected at random contains at most one small apple.



A crate contains 50 bags of apples. A crate is selected at random.
(i) Find the expected number of bags in this crate that contain at most one small apple.
(ii) Find the probability that at least 48 bags in this crate contain at most one small apple.










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$endgroup$

















    1












    $begingroup$


    I can solve the k, but I am not really able to do the rest!



    The mass M of apples in grams is normally distributed with mean μ . The following table shows probabilities for values of M .
    Values: M>93 -> p(x)=k
    93< M < 119 -> p(x)= 0.98
    119 < M -> p(x)= 0.01
    Part a:
    (i) Write down the value of k .
    (ii) Show that μ = 106.
    Part b:
    Find P (M < 95) .
    Part c and d:
    The apples are packed in bags of ten.Any apples with a mass less than 95 g are classiied as small.



    Find the probability that a bag of apples selected at random contains at most one small apple.



    A crate contains 50 bags of apples. A crate is selected at random.
    (i) Find the expected number of bags in this crate that contain at most one small apple.
    (ii) Find the probability that at least 48 bags in this crate contain at most one small apple.










    share|cite|improve this question











    $endgroup$















      1












      1








      1


      1



      $begingroup$


      I can solve the k, but I am not really able to do the rest!



      The mass M of apples in grams is normally distributed with mean μ . The following table shows probabilities for values of M .
      Values: M>93 -> p(x)=k
      93< M < 119 -> p(x)= 0.98
      119 < M -> p(x)= 0.01
      Part a:
      (i) Write down the value of k .
      (ii) Show that μ = 106.
      Part b:
      Find P (M < 95) .
      Part c and d:
      The apples are packed in bags of ten.Any apples with a mass less than 95 g are classiied as small.



      Find the probability that a bag of apples selected at random contains at most one small apple.



      A crate contains 50 bags of apples. A crate is selected at random.
      (i) Find the expected number of bags in this crate that contain at most one small apple.
      (ii) Find the probability that at least 48 bags in this crate contain at most one small apple.










      share|cite|improve this question











      $endgroup$




      I can solve the k, but I am not really able to do the rest!



      The mass M of apples in grams is normally distributed with mean μ . The following table shows probabilities for values of M .
      Values: M>93 -> p(x)=k
      93< M < 119 -> p(x)= 0.98
      119 < M -> p(x)= 0.01
      Part a:
      (i) Write down the value of k .
      (ii) Show that μ = 106.
      Part b:
      Find P (M < 95) .
      Part c and d:
      The apples are packed in bags of ten.Any apples with a mass less than 95 g are classiied as small.



      Find the probability that a bag of apples selected at random contains at most one small apple.



      A crate contains 50 bags of apples. A crate is selected at random.
      (i) Find the expected number of bags in this crate that contain at most one small apple.
      (ii) Find the probability that at least 48 bags in this crate contain at most one small apple.







      probability statistics






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      edited Dec 12 '18 at 13:24









      David G. Stork

      11k31432




      11k31432










      asked Dec 12 '18 at 10:30









      Dominik Dominik

      83




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          2 Answers
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          1












          $begingroup$

          Part a) $$P(Mgt 93) = 1-P(Mlt 93) = k$$



          $$P(Mlt 93) = 1-k$$



          $$P(93lt M lt 119) = 0.98$$



          $$P(Mgt 119) = 0.01$$
          Thus $$(1-k+0.98+0.01) = 1 implies k =0.99$$



          $$frac{119-mu}{sigma} = Phi^{-1}(0.99) = 2.326$$



          $$frac{93-mu}{sigma} = Phi^{-1}(0.01) = -2.326$$



          Adding the above we get



          $$frac{119-mu}{sigma}=-frac{93-mu}{sigma}$$



          $$implies mu = 106$$.



          Part b)$$P(M<95) = Phi(frac{95-106}{frac{13}{2.326}}) = p$$



          Part c) Atmost 1 apples be small in a bag of 10



          Use Binomial Distribution to find $P(Xle1)$



          $= {10choose 0} p^0 (1-p)^{10} + {10choose 1} p^1 (1-p)^9 = P$



          Part d) Expected Value$ = 50*P$



          $$P(Yge 48) ={50choose 48} P^{48} (1-P)^{2}+{50choose 49} P^{49}(1-P)^{1} +{50choose 50} P^{50}$$






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            $begingroup$

            Due to symmetry $k=0.01$ and $mu=(119+93)/2=106$. From $P(M<119)=0.99$ you'll find $sigma=5.588$. Thus $P(M<95)=0.0245$.



            For (c) and (d) use an appropriate Binomial Distribution.






            share|cite|improve this answer











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              2 Answers
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              active

              oldest

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              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              1












              $begingroup$

              Part a) $$P(Mgt 93) = 1-P(Mlt 93) = k$$



              $$P(Mlt 93) = 1-k$$



              $$P(93lt M lt 119) = 0.98$$



              $$P(Mgt 119) = 0.01$$
              Thus $$(1-k+0.98+0.01) = 1 implies k =0.99$$



              $$frac{119-mu}{sigma} = Phi^{-1}(0.99) = 2.326$$



              $$frac{93-mu}{sigma} = Phi^{-1}(0.01) = -2.326$$



              Adding the above we get



              $$frac{119-mu}{sigma}=-frac{93-mu}{sigma}$$



              $$implies mu = 106$$.



              Part b)$$P(M<95) = Phi(frac{95-106}{frac{13}{2.326}}) = p$$



              Part c) Atmost 1 apples be small in a bag of 10



              Use Binomial Distribution to find $P(Xle1)$



              $= {10choose 0} p^0 (1-p)^{10} + {10choose 1} p^1 (1-p)^9 = P$



              Part d) Expected Value$ = 50*P$



              $$P(Yge 48) ={50choose 48} P^{48} (1-P)^{2}+{50choose 49} P^{49}(1-P)^{1} +{50choose 50} P^{50}$$






              share|cite|improve this answer











              $endgroup$


















                1












                $begingroup$

                Part a) $$P(Mgt 93) = 1-P(Mlt 93) = k$$



                $$P(Mlt 93) = 1-k$$



                $$P(93lt M lt 119) = 0.98$$



                $$P(Mgt 119) = 0.01$$
                Thus $$(1-k+0.98+0.01) = 1 implies k =0.99$$



                $$frac{119-mu}{sigma} = Phi^{-1}(0.99) = 2.326$$



                $$frac{93-mu}{sigma} = Phi^{-1}(0.01) = -2.326$$



                Adding the above we get



                $$frac{119-mu}{sigma}=-frac{93-mu}{sigma}$$



                $$implies mu = 106$$.



                Part b)$$P(M<95) = Phi(frac{95-106}{frac{13}{2.326}}) = p$$



                Part c) Atmost 1 apples be small in a bag of 10



                Use Binomial Distribution to find $P(Xle1)$



                $= {10choose 0} p^0 (1-p)^{10} + {10choose 1} p^1 (1-p)^9 = P$



                Part d) Expected Value$ = 50*P$



                $$P(Yge 48) ={50choose 48} P^{48} (1-P)^{2}+{50choose 49} P^{49}(1-P)^{1} +{50choose 50} P^{50}$$






                share|cite|improve this answer











                $endgroup$
















                  1












                  1








                  1





                  $begingroup$

                  Part a) $$P(Mgt 93) = 1-P(Mlt 93) = k$$



                  $$P(Mlt 93) = 1-k$$



                  $$P(93lt M lt 119) = 0.98$$



                  $$P(Mgt 119) = 0.01$$
                  Thus $$(1-k+0.98+0.01) = 1 implies k =0.99$$



                  $$frac{119-mu}{sigma} = Phi^{-1}(0.99) = 2.326$$



                  $$frac{93-mu}{sigma} = Phi^{-1}(0.01) = -2.326$$



                  Adding the above we get



                  $$frac{119-mu}{sigma}=-frac{93-mu}{sigma}$$



                  $$implies mu = 106$$.



                  Part b)$$P(M<95) = Phi(frac{95-106}{frac{13}{2.326}}) = p$$



                  Part c) Atmost 1 apples be small in a bag of 10



                  Use Binomial Distribution to find $P(Xle1)$



                  $= {10choose 0} p^0 (1-p)^{10} + {10choose 1} p^1 (1-p)^9 = P$



                  Part d) Expected Value$ = 50*P$



                  $$P(Yge 48) ={50choose 48} P^{48} (1-P)^{2}+{50choose 49} P^{49}(1-P)^{1} +{50choose 50} P^{50}$$






                  share|cite|improve this answer











                  $endgroup$



                  Part a) $$P(Mgt 93) = 1-P(Mlt 93) = k$$



                  $$P(Mlt 93) = 1-k$$



                  $$P(93lt M lt 119) = 0.98$$



                  $$P(Mgt 119) = 0.01$$
                  Thus $$(1-k+0.98+0.01) = 1 implies k =0.99$$



                  $$frac{119-mu}{sigma} = Phi^{-1}(0.99) = 2.326$$



                  $$frac{93-mu}{sigma} = Phi^{-1}(0.01) = -2.326$$



                  Adding the above we get



                  $$frac{119-mu}{sigma}=-frac{93-mu}{sigma}$$



                  $$implies mu = 106$$.



                  Part b)$$P(M<95) = Phi(frac{95-106}{frac{13}{2.326}}) = p$$



                  Part c) Atmost 1 apples be small in a bag of 10



                  Use Binomial Distribution to find $P(Xle1)$



                  $= {10choose 0} p^0 (1-p)^{10} + {10choose 1} p^1 (1-p)^9 = P$



                  Part d) Expected Value$ = 50*P$



                  $$P(Yge 48) ={50choose 48} P^{48} (1-P)^{2}+{50choose 49} P^{49}(1-P)^{1} +{50choose 50} P^{50}$$







                  share|cite|improve this answer














                  share|cite|improve this answer



                  share|cite|improve this answer








                  edited Dec 13 '18 at 0:45

























                  answered Dec 12 '18 at 11:18









                  Satish RamanathanSatish Ramanathan

                  9,86531323




                  9,86531323























                      0












                      $begingroup$

                      Due to symmetry $k=0.01$ and $mu=(119+93)/2=106$. From $P(M<119)=0.99$ you'll find $sigma=5.588$. Thus $P(M<95)=0.0245$.



                      For (c) and (d) use an appropriate Binomial Distribution.






                      share|cite|improve this answer











                      $endgroup$


















                        0












                        $begingroup$

                        Due to symmetry $k=0.01$ and $mu=(119+93)/2=106$. From $P(M<119)=0.99$ you'll find $sigma=5.588$. Thus $P(M<95)=0.0245$.



                        For (c) and (d) use an appropriate Binomial Distribution.






                        share|cite|improve this answer











                        $endgroup$
















                          0












                          0








                          0





                          $begingroup$

                          Due to symmetry $k=0.01$ and $mu=(119+93)/2=106$. From $P(M<119)=0.99$ you'll find $sigma=5.588$. Thus $P(M<95)=0.0245$.



                          For (c) and (d) use an appropriate Binomial Distribution.






                          share|cite|improve this answer











                          $endgroup$



                          Due to symmetry $k=0.01$ and $mu=(119+93)/2=106$. From $P(M<119)=0.99$ you'll find $sigma=5.588$. Thus $P(M<95)=0.0245$.



                          For (c) and (d) use an appropriate Binomial Distribution.







                          share|cite|improve this answer














                          share|cite|improve this answer



                          share|cite|improve this answer








                          edited Dec 12 '18 at 11:51









                          farruhota

                          20.2k2738




                          20.2k2738










                          answered Dec 12 '18 at 11:19









                          Michael HoppeMichael Hoppe

                          11k31836




                          11k31836






























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