Question #
1:
a.
solution:
n=160 n=220
12
x1=15.80
x2=10.25
22
S=64
S=47
|
12
1-a=0.96
|
22
SS
|
12
(x1-x2)±Z+
|
a
|
nn
|
212
Z=0.48
|
a
2
a
|
Now see value of in the Z table
2
|
0.48 lie in the row 2.00 and lie in
the column 0.06
Z=2.00+0.06
a
|
2
|
Z=2.06
|
a
2
Now put values in formula,
|
6447
(15.80-10.25)±2.06+
|
160220
135
(5.55)±2.06
|
220
(5.55)±5.1088
5.55+5.10885.55-5.1088
,,,,,,,,,,
|
10.65880.3912
b.
Solution:
|
n=200 p=0.30
|
q=1-p=1-0.30=0.70
|
1-a=0.95
pq
|
|
p±Z
|
a
n
|
2
Z
|
a
2
a0.95
|
==0.475
22
|
a
Now see the value of in the Z table.
|
2
0.47 lies in 1.9 rows and 0.06
columns
Z=1.9+0.06
a
|
2
|
Z=1.96
|
a
2
Now put values in formula,
|
(0.30)(0.70)
0.30±1.96
|
200
0.30±1.96(0.0324)
0.30±0.063504
0.30+0.0635040.30-0.063504
,,,,,,,,,,
|
0.3640.236
Question
# 2:
Solution
Of part a:
e=0.30s
1-a=0.90
|
a=0.1
2
æZ
|
aö
1-
|
ç2÷
|
n=
|
ç÷
e
|
ç÷
|
èø
Z=Z
a0.95
|
1-
2
|
see the value of in Z table
Z=1.6449=1.645a
0.95
2
æ1.645sö
|
n=
|
ç÷
|
è0.30sø
|
n=30.07
Solution
of part b:
m=30 , s=5 , n=50
s
s=
|
x
n
|
5
s=
|
x
50
|
s=0.707
x