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(28 points] 10 pounds and standard deviation of 2 pounds. If a fish of this spec

ID: 3364641 • Letter: #

Question

(28 points] 10 pounds and standard deviation of 2 pounds. If a fish of this species is caught randomly, what is the probability of the following events? 3. Suppose the weight of a specific fish species is normally distributed with mean of a. Weight of the fish is less than 10 pounds? b. Weight of the fish is in between 7 pounds and 8.5 pounds? If two fish are caught randomly, what is the probability that the weights of both fish will be more than 9 pounds? c. d. Calculate the 80th percentile of weights of this type of fish.

Explanation / Answer

SolutionA:

mean=10

sd=2

P(X<10)

z=x-mean/sd

=10-10/2

=0

P(Z<0)

from standrad norma;l tables

P(Z<0)=0.5

ANSWER 0.5

Solutionb:

P(7<X<8.5)

P(7-10/2<Z<8.5-10/2)

=P(-1.5<z<-0.75)

From standard normal tables

P(-1.5<z<-0.75)=0.1598

ANSWER:0.1598

Solutionc:

n=2

P(X>9)

P(Z>9-10/2)/sqrt(2)

=P(Z>-0.71)

=P(Z<0.71)

=0.7611(from standard normal tables)

ANSWER :0.7611

Solutiond:

80h perecntile to z

Z=0.842

x-mean/sd=0.842

x-10/2=0.842

x-10=1.684

x=10+1.684

x=11.684

ANSWER:11.684