Comm215MTSolutionsWinter2011

Comm215MTSolutionsWinter2011 - Prep101 Comm215MTSolutions...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
©Prep101 Comm215 MT Solutions Solutions will be posted at www.prep101.com/solutions 1 2. Numerical Descriptive Techniques Problems Q1. Solution: a Arithmetic mean: n i i X n X 1 1 S D = n i i n i i X X n n X X 1 1 ) ( 1 ) ( = ] 1 1 [ 1 X n n X n n n i i = 0 ] [ X X n Q2. Solution: c Think of Normal distribution as an example. Q3. a) Solution: quantitative data, best depicted in a histogram b) Solution: qualitative data, best depicted in pie graph c) Solution: qualitative data, best depicted in bar graph d) Solution: quantitative, best depicted in scatterplot
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
©Prep101 Comm215 MT Solutions Solutions will be posted at www.prep101.com/solutions 2 Q4. a) Solution: Two different pie graphs b) Solution: Side-by-side bar chart c) Solution: The bar chart makes it easy to compare yearly changes, while the pie chart makes the relative shares more evident. There seems to be a trend towards increasing the amount of manufacturing outsourced. d) Solution: Both are the same
Background image of page 2
©Prep101 Comm215 MT Solutions Solutions will be posted at www.prep101.com/solutions 3 3. Association Between Quantitative Variables Problems Q1. a) Solution: 140 . 0 ) 3398 ( ) 701940 ( 20 ) 5 . 972 )( 3398 ( ) 8 . 182677 ( 20 ) ( ) )( ( 2 2 2 1 x x n y x xy n b x y x b y b o 140 . 0 839 . 24 ˆ 839 . 24 ) 20 3398 ( 140 . 0 20 5 . 972 1 b) Solution: If no cases are delivered, the delivery time is 24.8 minutes. for each additional case delivered, the delivery time increases by 0.14 minutes. c) Solution: 839 . 45 ) 150 ( 14 . 0 839 . 24 ˆ y The estimated delivery time is 45.8 minutes d) Solution: 986 . 0 r There is a strong, positive correlation between the number of cases delivered and the delivery time.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
©Prep101 Comm215 MT Solutions Solutions will be posted at www.prep101.com/solutions 4 Q2. a) Solution: 218 155 121 30 25 2 y x xy y x 859 . 0 190 150 145 ) 30 ( ) 218 ( 5 ) 25 ( ) 155 ( 5 ) 30 )( 25 ( ) 121 ( 5 ) ( ) ( ) )( ( 2 2 2 2 2 2 y y n x x n y x xy n r b) Solution: 967 . 0 150 145 ) 25 ( ) 155 ( 5 ) 30 )( 25 ( ) 121 ( 5 ) ( ) )( ( 2 2 2 1 x x n y x xy n b x y x b y b o 967 . 0 84 . 10 ˆ 84 . 10 ) 5 25 ( 967 . 0 5 30 1 Q3. a) Solutions: 2 2 2 2 ) ( ) ( ) )( ( y y n x x n y x xy n r 2 2 649 ) 8500 ( 5 689 ) 97463 ( 5 ) 649 )( 680 ( ) 91490 ( 5 8754 12594 10289 = 0.980 There is a strong, negative correlation between the amount of chemical used and the number of surviving beetles.
Background image of page 4
©Prep101 Comm215 MT Solutions Solutions will be posted at www.prep101.com/solutions 5 b) Solutions: The correlation coefficient would remain the same since it is not affected by a linear transformation of x or y. c) Solution: 1 2 ) ( 2 n x s n x x y x s s r b n x x n y y 4 97463 5 ) 689 ( 2 09 . 25 92 . 20 980 . 0 b 5 689 5 649 09 . 25 x s 1 5 85991 5 ) 689 ( 2 y s a 92 . 20 y s ) 3 . 137 ( 817 . 0 8 . 129 a 22 . 17 a y 17.22 0.817 x Q4.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/29/2012 for the course COMM 215 taught by Professor Online during the Spring '12 term at Concordia CA.

Page1 / 28

Comm215MTSolutionsWinter2011 - Prep101 Comm215MTSolutions...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online