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People visiting video rental stores often rent more than one DVD at a time. The probability distribution for DVD rentals per customer at Video To Go is given in the following table. There is a five-video limit per customer at this store, so nobody ever rents more than five DVDs.

a. Describe the random variable Xin words.

b. Find the probability that a customer rents three DVDs.

c. Find the probability that a customer rents at least four DVDs.

d. Find the probability that a customer rents at most two DVDs.

Another shop, Entertainment Headquarters, rents DVDs and video games. The probability distribution for DVD rentals per customer at this shop is given as follows. They also have a five-DVD limit per customer.

e. At which store is the expected number of DVDs rented per customer higher?

f. If Video to Go estimates that they will have 300customers next week, how many DVDs do they expect to rent next week? Answer in sentence form.

g. If Video to Go expects 300customers next week, and Entertainment HQ projects that they will have420customers, for which store is the expected number of DVD rentals for next week higher? Explain.

h. Which of the two video stores experiences more variation in the number of DVD rentals per customer? How do you know that?

Short Answer

Expert verified

(a) X is the quantity of DVDs on rent per customer.

(b)0.12.

(c) 0.11.

(d)0.77.

(e) At the Entertainment Headquarters, the expected number of DVDs rented per customer is higher

(f)546

(g)588

(h) The entertainment headquarters has more variation

Step by step solution

01

Given Information 

Given a table of the probability distribution for DVD rentals per customer at the video rental store.

02

Explanation (Part a)

X is the quantity of DVDs on rent per customer

03

Explanation (Part b)

The likelihood of just someone leasing three DVDs is

P(X=3)=10.030.50.240.070.04=0.12

04

Explanation (Part c)

The probability that the customer takes at least4DVDs is

P(X4)=P(X=4)+P(X=5)=0.07+0.04=0.11

05

Explanation (Part d)

The probability that the customer takes two or more DVDs is

P(X2)=P(X=0)+P(X=1)+P(X=2)=0.03+0.5+0.24=0.77

06

Explanation (Part e) 

In the first store, the value obtained from supplied DVDs is

μ1=i=05i.P(X=i)=00.03+10.5+20.24+30.12+40.07+5=0+0.5+0.48+0.36+0.28+0.2=1.82

The value obtained from Entertainment headquarters:

μ1=i=05iP(X=i)=00.35+10.25+20.2+30.1+4=0+0.25+0.4+0.3+0.2+0.25=1.4

Hence the predicted amount of DVDs acquired by a visitor is higher.

07

Explanation (Part f)

For Video To Go The expected value is,

Expected value isx.Px

=0×0.03+1×0.5+2×0.24+3×0.12+4×0.07+5×0.04=1.82

Hence, the number of videos expectedly rented to300video To Go customers are

300×1.82=546

08

Explanation (Part g)

For Video To Go the expected value is

Expected value

=x.Px

=0×0.03+1×0.5+2×0.24+3×0.12+4×0.07+5×0.04=1.82

The value of Entertainment Headquarters is expected as

Expected value =x.Px

=0×0.35+1×0.25+2×0.20+3×0.10+4×0.05+5×0.05=1.4

The expected number of videos rented is300×1.82=546

For the videos rented to the expected number is

420×1.4=588

09

Explanation (part h)

The expected value of Video To Go is:

Expected value=x.Px

=0×0.03+1×0.5+2×0.24+3×0.12+4×0.07+5×0.04=0+0.5+0.48+0.36+0.28+0.2=1.82

The expected value of Entertainment Headquarters is:

Expected value=x.Px

=0×0.35+1×0.25+2×0.20+3×0.10+4×0.05+5×0.05=0+0.25+0.4+0.3+0.2+0.25=1.4

Calculating the quality deviations from both sets

σ1=i=05xiμ12P(X=i)=0-1.822×0.03+1-1.822×0.50+2-1.822×0.24+3-1.822×0.12+4-1.822×0.07+5-1.822×0.04=1.161σ2=i=05xiμ22P(X=i)=0-1.42×0.35+1-1.42×0.25+2-1.42×0.20+3-1.42×0.10+4-1.42×0.05+5-1.42×0.05=1.429

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