Apps. and Interpretation for IBDP Maths Ebook 2 | Page 357

Answers
78.3 ( a ) ( i ) H
0
: p � 0.03
( ii )
H
1 : p �
0.03
( b )
( i )
7
( ii )
6
78.4
( a )
( i )
H
0 : � �
2.5
( ii ) H
1
: � � 2.5
( b )
( i )
8
( ii )
7
79.4 ( a ) ( i ) H
0
: � � 100
( b )
0.134
( c )
0.499
( ii ) H
1
: � � 100
( d ) Y � 24.1
( e ) The null hypothesis is rejected as the sample mean is less than 24.1 .
( f ) Y � 23.7
Exercise 79
79.1 ( a ) ( i ) H
0
: � � 9
( ii )
H
1 : � �
9
( b )
0.0739
( c )
0.573
( d )
0�Y �
4
( e )
0.0367
( f )
The null hypothesis is not
rejected as p-value �
0.01.
79.2
( a )
( i )
H
0 : q �
0.92
( ii )
H
1 : q �
0.92
( b )
0.0827
( c )
0.810
( d )
Y �
7
( e )
0.185
( f )
The null hypothesis is not
rejected as p-value � 0.05
.
79.3
( a )
( i )
H
0 : � �
250
( b )
0.0127
( c )
0.868
( ii ) H
1
: � � 250
( d ) Y � 298 or Y � 302
( e ) The null hypothesis is rejected as the sample mean is less than 298 .
( f ) Y � 299 or Y � 301
Exercise 80
80.1 ( a ) ( i ) H
0
: � � 0
( ii ) H
1
: � � 0 ( b ) p-value � 0.00119
( c )
The null hypothesis is
rejected as p-value �
0.1.
( d )
( i )
a �� 4.24 , b �
99.2
( ii )
b represents the expected quiz score of a student who didn ’ t revise .
( e )
69.5 marks
( f )
( i )
r ��
0.960
2
( ii ) R � 0.921
( iii ) 92.1 % of the variability of the data is explained by the regression model . www . seprodstore . com
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