Assignment 2

Source file ⇒ Assignment_2.Rmd

Book Problems

2-7.

1. There are 16 variables.
2. There are 336776 cases.
3. Each case represents the “on-time data for all flights that departed NYC in 2013”
4. • year - categorical
   • month - categorical
   • day - categorical
   • dep_time - categorical
   • arr_time - categorical
   • dep_delay - quantitative
   • arr_delay - quantitiative
   • hour - categorical
   • minute - categorical
   • carrier - categorical
   • tailnum - categorical
   • flight - categorical
   • origin - categorical
   • destination - categorical
   • air_time - quantitative
   • distance - quantitative
5. air_time is measured in minutes and distance is measured in miles.

2-8.

a. Improper syntax for funtion argument

b. No assignment operator

c. Invalid object name

d. Unmatched quotes in character string

e. No mistake

2-10.

• CountryData has 76 variables.

• The variable tfat measures “mass of trunk fat” in the NCHS data table.

• In WorldCities, there are 23018 cases:

• The third variable in BabyNames is count.

• The codes for the levels of the categorical variable party in RegisteredVoters is DEM=Democratic, LIB=Libertarian, REP=Republican, and UNA=Unaffiliated

3-4.

1. data table name
   2. function name
   3. variable name
   4. function name
2. function name
   6. variable name
   7. variable name
   8. function name
3. variable name
   10. function name
   11. variable name
   12. function name
4. function name
   14. name of named argument
   15. name of named argument
   16. function name
5. name of named argument
   18. function name
   19. name of named argument

3-5.

• The meaning of the brainwt variable is an animal’s brain weight in kilograms.
• There are 83 cases.
• Each case represents a mammal.
• The levels of the vore variable are “carnivore”, “omnivore”, and “herbivore”.

3-6.

3. does not fit as it takes the mean of count rather than the sum

4-1.

1. italics

2. bold

• 3. Bullet

4. Header

5. code

6. Subheader

4-5.

Go to http://rpubs.com/dbalonzo/birds

Basics

The Data Set Inv has 2000 cases and 18 variables. Each case can be interpreted as a different item in the library inventory .Some of these variables include where the item is located, the author of the item, the number of times the item has been issued, and more.

The Data Set Bks has 3765 cases and 15 variables. Each case represents a book. These variables include the books author, publisher, publication date, and more.

## Source: local data frame [4 x 2]
## 
##   Current.Status     n
##            (chr) (int)
## 1      AVAILABLE  1866
## 2        MISSING     1
## 3        ON_LOAN    18
## 4      WITHDRAWN   115

• The table above displays the current status of books with the status and counts the number of books with that status.
• Ex: The number of books in inventory with status “available” is 1866.

## Source: local data frame [46 x 2]
## 
##    Issued.Count     n
##           (int) (int)
## 1             0   996
## 2             1   337
## 3             2   203
## 4             3   121
## 5             4    69
## 6             5    46
## 7             6    38
## 8             7    29
## 9             8    24
## 10            9    20
## ..          ...   ...

• The table above shows number of books that have been issued for a certain amount of times
• Ex: There are 203 different books that have been issued 2 times.