Question

Strands Copper wire from a manufacturer are analyzed forstrenghth and conductivity. The Results from 100 strands are asfollows:Strength StrengthHigh Lowhigh conductivity 74 8low conductivity 15 3a) If a stand is randomly selected, what is the probabilitythat is conductivity is high and its strength is high)b) If a stand is randomly selected, what is the probabilitythat its conductivity is low or strength is low?c) Consider the event that a strand hs low conductivity andthe event that the strand has a low strength. Are these tow eventsmutually exclusive?

Answer 1

Answer and explanation:

Given : Strands Copper wire from a manufacturer are analyzed forstrenghth and conductivity. The Results from 100 strands are as follows :

                                                 Strength Strength

                                                    High             Low

High conductivity                         74                8

Low conductivity                         15                3

To find :

a) If a stand is randomly selected, the probability that is conductivity is high and its strength is high

The favorable outcome is 74

The probability is given by,

$P=\frac{74}{100}=0.74$

b) If a stand is randomly selected, the probability that its conductivity is low or  strength is low

Conductivity is low A= 15+3=18

Strength is low B= 8+3=11

Conductivity is low and  strength is low $A\cap B=3$

Probability is given by,

$P(A\cup B)=P(A)+P(B)-P(A\cap B)$

$P(A\cup B)=\frac{18}{100}+\frac{11}{100}-\frac{3}{100}$

$P(A\cup B)=0.18+0.11-0.03$

$P(A\cup B)=0.26$

c) Consider the event that a strand low conductivity and the event that the strand has a low strength. Are these tow events mutually exclusive?

Since the events the stand has low conductivity and the stand has low strength  are not mutually exclusive, since there exists some cases in which both the  events coincide. i.e. Intersection of both the events exists with probability 0.03.