Apps. and Interpretation for IBDP Maths Ebook 2 | Page 358

Your Practice Set – Applications and Interpretation for IBDP Mathematics
80.2 ( a ) ( i ) H
0
: � � 0
( ii ) H
1
: � � 0 ( b ) p-value � 0.0164
( c )
The null hypothesis is
rejected as p-value �
0.05.
( d )
( i )
a � 0.937 , b ��
5.07
( ii )
a represents the average increase in the number of webpages visited when the time for accessing the internet is increased by 1 minute .
( e )
16
( f )
( i )
r �
0.893
( ii )
2 R �
0.798
( iii )
79.8 % of the
variability of the data is explained by the
regression model .
80.3
( a )
( i )
H
0 : � �
0
( ii ) H
1
: � � 0 ( b ) p-value � 0.519
( c ) The null hypothesis is not rejected as p-value � 0.05 .
( d ) This suggestion is not a valid approach as from the result of the hypothesis test , the two variables are weakly correlated .
( e )
( i )
2 R �
0.000861
( ii )
0.861 % of the variability of the data is explained by the regression model .
( f )
SSres
�
18822
( g ) SStot
� 195000
80.4 ( a ) ( i ) H
0
: � � 0
( ii ) H
1
: � � 0 ( b ) p-value � 0.181
( c ) The null hypothesis is not rejected as p-value � 0.1.
( d ) This suggestion is not a valid approach as from the result of the hypothesis test , the two variables are weakly correlated .
( e )
( i )
2 R �
0.278
( ii )
27.8 % of the variability of the data is explained by the regression model .
( f )
SSres
�
131.6875
( g ) SStot
� 314
Chapter 20
Quick Practice
I
( a )
( 1 )
a �� 0.748 , b � 11.5
, c �� 57.9 , d �
451
( 2 )
354
( 3 )
This estimation is valid as this is an interpolation .
( b )
( 1 )
346.2
( 2 )
H
0 : � �
370
( 3 )
H
1 : � �
370
( 4 )
p-value �
0.0313
( 5 ) The null hypothesis is rejected as p-value � 0.05.
II ( c ) ( 1 ) 403.91�
0.97911 n
2
( 2 ) R � 0.971
( 3 ) 97.1 % of the variability of the data is explained by the regression model .
348
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