Description
Exam 1: ECN 221
Types of Data
Qualitative
Desen Pine! Nominal Ordinal
• No ranking alloud Ponting allowd
Quantitative
numerical data Interval
· Ranilang allowed . All chavecensics of
SE
No WC O pointi ALWAVS numento
. can be sumenc .no measurable or nonimgic meaning to
manife! TYMCO paint
SIE
TT
395
Zipcodes Mome ownership
credit scor 6 PA temperature INCOM € education level
Population USCA 2 CA cross sectionali vaines para ja
collected durdag cigie time period
Don't forget about the age old question of What does scientific development mean?
2009
population
2010
over a range of
sample Don't forget about the age old question of How do marginal costs and benefits relate to trade offs?
We also discuss several other topics like What is the difference between arithmetic and algebra?
Descriptive => Summarize
Inferential >> making statements
by examining sample
S
sample: o 22
14 3
3 550
(n=10)
Bel. Freq. Cum Rel. Freq. 0172/10  0:2 0:2 Don't forget about the age old question of What is legitimate political authority based on?
1110 On 0.220.1*0.3 2110 =0.2 0,3+ 0.20.5 12/10 +0.2 10.5*0,2 = 0.7
5 1
2
12/10 0.2
0.8 +0.25 1.0
10
'I = 10 We also discuss several other topics like How does axial stress vary from neutral axis?
Discrete Data : values that can bc COUNTED
les ex0,1,2,3. Children, vacation days continuas data: Balues that take on any real # Cincluding
decimal points We also discuss several other topics like What is the meaning of london forces in intermolecular interactions?
ex) time, weight class width: Solve for k=> 2 >n where K = of classes
n of data por est. class width: max volne min value
W
TS
example: 2 >n
2 > 10 K3.32 cround wp!)
k=4
class width: 50 =574= 1,25 rounded 2]
Measures of Central
INTILISSION
Generally used
there are shers
(no other's

If the data Mode Categorcaj
US
there are
Median outlets
Population
Sample
index point
the value that OCCUYS Most
Stud Soup
episode
OS
* If not whole,
round wp* * when nis
even, mediana
Zscore? Z = XX X
M
CANA
Distribution Shape
TRICOU
Symmetric
Syewed
(mean = median
FEN
EVEN
Left Creaviz median
cmean >median)
Per
Measures of Variability
DOELTR
E
S
Range
Variance Lysample: st 6 (Xiat
standard deviation Lsamples
Largest Valuea smallest value
b> Population 
Empirical Rule
CF
Coefficient of
Variationlov) 2000)
100er
Tu38 / 20 / 40 uro a lot
IL
PA (100)
Measures of Relative
Position
www
Percentile
ber
Quartiles 115425** percengle () 4 and 50 percentile caz) L 3*75per cento de las)
where P= percentile
Measures of
Association
or
covariance
br. Sxy
correlation Lx indicates strength
relationship between
2 variables L ranges from  1 Le correlation causation!
= E(x7)(y 13(x772&cyjo
ramy ECX  ED cy  jo
Sx
Sy