Assignment 4A
Total Marks = s
Please show all your work. Some questions require you to use graphs, tree
diagrams, fornmlas. and so on that are difficult or impossible to reproduce
in word-pl'O('essing programs, so you will have to print the entire
assignment and fill it out and mail it to your tutor. As an alternative to
mailing. you might be able to photograph or scan your assignment and
submit it through the appropriate drop box. If you do, make sure the
material you are submitting is legible.
Question 1
Grade point aYerages of math majors at a large distance education
uniYersity are normally distributed with a mean of µ =2.85 and a standard
de,iation of a-= 0.30 . If a random sample of 25 math majors is selected
from that university, what is the probability that the sample mean grade
point aYerage , ...;n be
6marks a. either less than 2.709 or more than 2.955?
3marks b . at least 2.757?
:\
C (T -
s IJ\:: 2 5 - -cr-
~-µ
r ( x < 2 101 ~ n : < - 2. s)
6 30
1r Tis-=
Ox -c : (),00~4
s o.Ob
f( x_> : .9S'j') : ?C z> l,75 )
~ I - 0.154"'
:: 0,()_;\0'
2. 7S7 - 2 is
~ C 215 D 0~
: - \.S5 r cK ~ 1.757) -= r c ~ -1. ss')
2
trx : oo~ = \ - o o60b
u : 0 ~o :: ( ~3~4
Y\· 25
- I ~5
Introduction to Statistics
1
, Question 2
Psychologists estimate that 80% of male drivers, when lost in trying to find
a location, continue to drive rather than asking for directions. If this
estimate is correct, what is the probability that, in a random sample of 100
lost male drivers, the proportion who continue to drive is
4 marks a. at least 0 .70?
3 marks b. less than 0 .85?
"') P" oia t : o 2.0 V'\ =100
: r1f ~ ..ro.~Q,1 :: Q. 04
),,, ~ -V~ U
X
!Oll
Q GO(,Z ~
" 0
'
P(~ > 0.10., p(z ?. O.7D - 0.t ): f (-z ?_ -2.S) -= \ - 0.1~31
0.04
Q 5p 0
0.0~
0
fC~ < o.\SJ : P(z< o_J50.0
0
- } J=P(.:: <1.1s = o.~i44
2
Mathematics 215 / Assignment 4A
Total Marks = s
Please show all your work. Some questions require you to use graphs, tree
diagrams, fornmlas. and so on that are difficult or impossible to reproduce
in word-pl'O('essing programs, so you will have to print the entire
assignment and fill it out and mail it to your tutor. As an alternative to
mailing. you might be able to photograph or scan your assignment and
submit it through the appropriate drop box. If you do, make sure the
material you are submitting is legible.
Question 1
Grade point aYerages of math majors at a large distance education
uniYersity are normally distributed with a mean of µ =2.85 and a standard
de,iation of a-= 0.30 . If a random sample of 25 math majors is selected
from that university, what is the probability that the sample mean grade
point aYerage , ...;n be
6marks a. either less than 2.709 or more than 2.955?
3marks b . at least 2.757?
:\
C (T -
s IJ\:: 2 5 - -cr-
~-µ
r ( x < 2 101 ~ n : < - 2. s)
6 30
1r Tis-=
Ox -c : (),00~4
s o.Ob
f( x_> : .9S'j') : ?C z> l,75 )
~ I - 0.154"'
:: 0,()_;\0'
2. 7S7 - 2 is
~ C 215 D 0~
: - \.S5 r cK ~ 1.757) -= r c ~ -1. ss')
2
trx : oo~ = \ - o o60b
u : 0 ~o :: ( ~3~4
Y\· 25
- I ~5
Introduction to Statistics
1
, Question 2
Psychologists estimate that 80% of male drivers, when lost in trying to find
a location, continue to drive rather than asking for directions. If this
estimate is correct, what is the probability that, in a random sample of 100
lost male drivers, the proportion who continue to drive is
4 marks a. at least 0 .70?
3 marks b. less than 0 .85?
"') P" oia t : o 2.0 V'\ =100
: r1f ~ ..ro.~Q,1 :: Q. 04
),,, ~ -V~ U
X
!Oll
Q GO(,Z ~
" 0
'
P(~ > 0.10., p(z ?. O.7D - 0.t ): f (-z ?_ -2.S) -= \ - 0.1~31
0.04
Q 5p 0
0.0~
0
fC~ < o.\SJ : P(z< o_J50.0
0
- } J=P(.:: <1.1s = o.~i44
2
Mathematics 215 / Assignment 4A
