Central Limit Theorem: Review
1.7
2008/06/19 15:06:23 GMT-5
2008/08/15 11:44:57.740 GMT-5
Barbara
Illowsky
illowskybarbara@deanza.edu
Susan
Dean
deansusan@deanza.edu
Connexions
cnx@cnx.org
elementary
statistics
The next three questions refer to the following information:
Richard’s Furniture Company delivers furniture from 10 A.M. to 2 P.M. continuously and uniformly. We are interested in how long (in hours) past the 10 A.M. start time that individuals wait for their delivery.
X
size 12{X "~" } {}
~
- A
U
(
0,4
)
size 12{U \( 0,4 \) } {}
- B
U
(
10
,
2
)
size 12{U \( "10",2 \) } {}
- C
Exp
(
2
)
size 12{ ital "Exp" \( 2 \) } {}
- D
N
(
2,1
)
size 12{N \( 2,1 \) } {}
A
The average wait time is:- A 1 hour
- B 2 hour
- C 2.5 hour
- D 4 hour
B
Suppose that it is now past noon on a delivery day. The probability that a person must wait at least
1
1
2
size 12{1 { {1} over {2} } } {}
more hours is:- A
1
4
size 12{ { {1} over {4} } } {}
- B
1
2
size 12{ { {1} over {2} } } {}
- C
3
4
size 12{ { {3} over {4} } } {}
- D
3
8
size 12{ { {3} over {8} } } {}
A
Given:
X~Exp(13) size 12{X "~" ital "Exp" \( { {1} over {3} } \) } {}.- a Find
P(X>1) size 12{P \( X>1 \) } {}
- b Calculate the minimum value for the upper quartile.
- c Find
P(X=13) size 12{P \( X= { {1} over {3} } \) } {}
- a 0.7165
- b 4.16
- c 0
- 40% of full-time students took 4 years to graduate
- 30% of full-time students took 5 years to graduate
- 20% of full-time students took 6 years to graduate
- 10% of full-time students took 7 years to graduate
The expected time for full-time students to graduate is:
- A 4 years
- B 4.5 years
- C 5 years
- D 5.5 years
C
Which of the following distributions is described by the following example?
Many people can run a short distance of under 2 miles, but as the distance increases, fewer people can run that far.
- A Binomial
- B Uniform
- C Exponential
- D Normal
C
The length of time to brush one’s teeth is generally thought to be exponentially distributed with a mean of
3
4
size 12{ { {3} over {4} } } {}
minutes. Find the probability that a randomly selected person brushes his/her teeth less than
3
4
size 12{ { {3} over {4} } } {}
minutes.
- A 0.5
- B
3
4
size 12{ { {3} over {4} } } {}
- C 0.43
- D 0.63
D
Which distribution accurately describes the following situation?
The chance that a teenage boy regularly gives his mother a kiss goodnight (and he should!!) is about 20%. Fourteen teenage boys are randomly surveyed.
X= size 12{X={}} {}the number of teenage boys that regularly give their mother a kiss goodnight
- A
B
(
14
,
0
.
20
)
size 12{B \( "14",0 "." "20" \) } {}
- B
P
(
2
.
8
)
size 12{P \( 2 "." 8 \) } {}
- C
N
(
2
.
8,2
.
24
)
size 12{N \( 2 "." 8,2 "." "24" \) } {}
- D
Exp
(
1
0
.
20
)
size 12{ ital "Exp" \( { {1} over {0 "." "20"} } \) } {}
A