Previously, De Anza statistics students estimated that the amount of change daytime statistics students carry is exponentially distributed with a mean of \(0.88. Suppose that we randomly pick 25daytime statistics students.

a. In words,Χ=____________

b.Χ~_____(_____,_____)

c.role="math" localid="1651578876947" Inwords,X=____________

d. X~______(______,______)

e. Find the probability that an individual had between \)0.80and\(1.00. Graph the situation, and shade in the area to be determined.

f. Find the probability that the average of the 25 students was between \)0.80and$1.00. Graph the situation, and shade in the area to be determined.

g. Explain why there is a difference in part e and part f.

Short Answer

Expert verified

a. Χ=amount of change students carry

b. X~E(0.88,0.88)

c. X=average amount of change carried by a sample of25sstudents.

d. X¯~N(0.88,0.176)

e. 0.0819

f.0.1882

g. The distributions are different. Part a is exponential and part b is normal.

Step by step solution

01

Given information

the amount of change daytime statistics students carry is exponentially distributed with a mean of $0.88. Suppose that we randomly pick 25daytime statistics students.

02

Explanation (part a)

According to the given information, the random variable is defined as,

Χ=amount of change students carry

03

Explanation (part b)

According to the given information, the random variable can be expressed as,

X~E(0.88,0.88)

04

Explanation (part c)

The other words of definition as follows:

X=average amount of change carried by a sample of 25 students.

05

Explanation (part d)

In other words, part d can be expressed as,

X¯~N(0.88,0.176)

06

Explanation (part e)

the probability that an individual had between $0.80and$1.00.

P(0.8<x<1)=(1-e-0.88×1)-(1-e-0.88×0.8)P(0.8<x<1)=0.4946-0.4127P(0.8<x<1)=0.0819

07

Explanation (part f)

the probability that the average of the 25students was between $0.80and$1.00.

P(0.80.88)0.88/(25)Z(10.88)0.88/(25)=P(0.4545Z0.68181)=0.1882

08

Explanation (part g)

The distributions are different. Part a is exponential and part b is normal.

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