Chapter 2: Statistical Variation Flashcards Preview

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Flashcards in Chapter 2: Statistical Variation Deck (20):
0

X or Y = ??

variables that are measured...

1

N =?

total number of subjects or scores...
n=subsample of the sample..
N= the total sample

2

Xi=??

i can vary from 1-N......the iTH score..

3

Summation?
N
Σχi
i= 1

N= last score in summation..
x= variable...
i= first score in the summation...
summation= sum of data..

4

Scales of measurement ?

determine types of tests used to analyze
different scales have different properties....

5

Properties of Measurement Scales?

Property of identity..
equal unit size...
absolute zero
magnitude/ordinality

6

Property of Identity ..

each value represents a descriptive category..
ex: drink brand, religious affiliation...

7

Property of Magnitude/ ordinality..

assigned values reflect greater than and less than...
grading scheme = ex !

8

Property of Equal unit size?..

difference between numbers are the same.....
ex: 120-130...and 180-190

9

Property of Absolute zero?

zero represents nothing of the variable...
.......# of cars in a parking lot? zero? zero= no cars....ex

10

Types of scales?? 4

Nominal, ordinal, interval and ratio scales...

11

Nominal Scale
property involved?

lowest scale of measurement
deals with qualitative data not quantitative data..
property = identity
no value difference between variables....
cannot add or avg..
good for comparisons ....how many of something...

12

Ordinal Scale?
Property?

deals with data that can be ordered or ranked....
ex: olympic race..... 1st , 2nd , 3rd
there are no in between numbers..
property: identity, magnitude..
A>B B>C ... A=F

13

Interval Scale?
property?

distance between ranked differences are =
Property: identity, magnitude, and interval properties..
zero is arbitrary..
can: a-b=c ..c-d...a-b>c-d..
cant do ratios no mult or divison...

14

Ratio Scale?
property?

Interval with true zero point....
score of zero = no amount of variable!
Property: identity, magnitude, equal interval and absolute zero!
can do all math operations...

15

Discrete Variables?
scales?

no possible values between adjacent units...
whole numbers units or categories...
cant have 3 and a half cats!
nominal and ordinal!

16

Continuous Variables..
scales?

can take infinite variable values in between units...
ex: drug dosage....10mg..10.1 mg...etc..
interval or ratio!

17

Real Limit?

values are set at 1/2 of the scale.....
score of 72 really means 72 +/- 0.5
URL: 72.5
LRL: 71.5

18

Upward Rounding bias?

we round up more times than we round down...

19

Solution to upward rounding bias!?

remainder is >5, round up
Remainder is <5, round down
Remainder is = 5 and last digit even, round down
Remainder is = 5 and last digit is odd, round up
ex: 26.6= 27
25.5 = 26...