Let Y denote the number of broken eggs in a randomly selected carton of one dozen “store brand” eggs at a local supermarket. Suppose that the probability distribution of Y is as follows.

Valueyi01234
ProbabilityPi0.78
0.11
0.07
0.03
0.01

a. What is the probability that at least 10 eggs in a randomly selected carton are unbroken?

b. Calculate and interpret μY.

C. Calculate and interpret σY.

d. A quality control inspector at the store keeps looking at randomly selected cartons of eggs until he finds one with at least 2 broken eggs. Find the probability that this happens in one of the first three cartons he inspects.

Short Answer

Expert verified
  1. The required probability is 0.96.
  2. The resultant mean is 0.38.
  3. The standard deviation is 0.822.
  4. The probability is 0.295.

Step by step solution

01

Part (a) Step 1: Given information

The following is the probability distribution:

Value01234
Probability0.780.110.070.030.01
02

Part (a) Step 1:  Calculation

At most two eggs are broken if at least ten eggs are undamaged.

The following formula can be used to compute the probability:

P(Y=2)=P(Y=0)+P(Y=1)+P(Y=2)=0.78+0.11+0.07=0.96

Thus, the required probability is 0.96.

03

Part (b) Step 1: Given information

The following is the probability distribution:

Value01234
Probability0.780.110.070.030.01
04

Part (b) Step 2: Calculation

The average can be calculated as follows:

Mean=y×P(y)=0(0.78)+1(0.11)+2(0.07)+3(0.03)+4(0.01)=0.38

The predicted number of broken eggs are 0.38

05

Part (c) Step 1: Given information

The following is the probability distribution:

Value01234
Probability0.780.110.070.030.01
06

Part (c) Step 2: Calculation

Calculate the standard deviation value,

σ=y2×P(y)-y×P(y)2=02×0.78+12×0.11+.+42×0.01-(0.38)2=0.822

The number of broken eggs is expected to differ by 0.822 from the mean of 0.38 eggs.

07

Part (d) Step 1: Given information

The following is the probability distribution:

Value01234
Probability0.780.110.070.030.01
08

Part (d) Step 2: Calculation

The chances of receiving at least two cracked eggs are:

P(Y2)=P(Y=2)+P(Y=3)+P(Y=4)=0.07+0.03+0.01=0.11

Now,

P(X=1)=0.11(1-0.11)1-1=0.11P(X=2)=0.11(1-0.11)2-1=0.0979P(X=3)=0.11(1-0.11)3-1=0.087131

Thus, the resultant probability is:

P(1X3)=P(X=1)+P(X=2)+P(X=3)=0.11+0.0979+0.087=0.295

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