Stats
Business 1020 with Adams at University of Colorado Boulder
About this deck
By: Jackie Livingston
Textbook:
Essentials of Statistics for Business and Economics (with CD-ROM)
Created: 2011-02-09
Size: 40 flashcards
Views: 107
Textbook:
Essentials of Statistics for Business and Economics (with CD-ROM)Created: 2011-02-09
Size: 40 flashcards
Views: 107
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
Kathy
Sign up (free) to study this.
Individual vs. Variable
The thing we count
vs.
Characteristic about the individual
Categorical vs. Numerical
Groups
vs
Numbers
Qualitative
Coded
Binary
yes or no, true of false
Quantitative
Discrete
countable
Continous
fraction or decimal
Categorical (2 Types)
Nominal: categories only, no avg, ex: male, female
Ordinal: rank has meaning, no avg, ex: freshman, sophomore, junior, senior
Numerical (2 Types)
Interval: distance has no meaning, ex: temperature (0)
Ratio: meaningful zero, ex: scales
Likert Scale
special case of interval data, values may not be numerical, intervals between are consistent
Example:
How would you rate your cell phone service
a)very poor
b)poor
c)average
d)good
e)very good
Time Series vs Cross Sectional
Time Series: trends and patterns over time
Cross Sectional: single point in time
Sample or Census?
Sample: infinite population, timely results, accuracy, cost
Census: small population, large sample, database, laws
Parameter vs Statistic
Parameter: unkown, fixed if population stays the same, N items
Statistic: estimate for the parameter, changes from sample to sample, n items
SImple Random Sample
redues bias
Stratified Sample
SRS from strata or similar groups within a population
Cluster Sample
geographical regions to define strata
Nonrandom Sample Methods
Judgement Sample
Conveience Sample
Both can lead to bias and should be avoided
What are we looking for?
Central Tendency
Dispersion
Shape
Dot Plots
unvariable
numerical
not for large samples
not much as for shape
Histogram (Numbers)
From frequency distribution
Still unvariable
Bins, numbers, width and limits, bins touch
Modal class ---> how many bars stick our among the rest
Gives us shape
Line Chart
Time Series (x axis)
More than one variable possible, line per variable
zero origin
gridlines
data markers
Bar Chart (Category- bins dont touch)
categorical data
can be used for time series
pareto ---> descending levels of frequency, defects and problems
Scatter Plots
Correlation
Line of best fit
Examine assosiation
Pie Chart
general idea of data
2 to 3 slices are ideal
Variance
describes how the data vary about the mean
the square root of the variance equation = Standard Diviation
Coefficient of Variation
(Variance / Mean) * 100 = CV
Empirical Rule (only for normal distribution/bell shaped)
68% fall wihin 1 standard deviation
95% fall within 2
99.73% fall within 3
Standard Deviation
The amount 3 standard deviations above and below the mean / 6 = standard deviation
Unusual & Outlier
Unusual: more than 2 standard deviations
Outlier: more than 3
Quartiles
Q1: bottom 25%
Q2: median
Q3: top 25%
Chebyshev's Therom
Atleast 75% within +or- 2 standard deviations
Atleast 88.9% within +or- 3
Empirical
no prior knowledge
assign probablity using f/n
law of large numbers
Classical
prior knowledge
not common in business
Subjective
No repeatable random expeirement
Mutually Exclusive Events
two events that cannot occur at the same time aka disjoint
Special law of addition
P(A or B) = P(A) + P(B) because P(A and B) = 0
Collectively Exhaustive
union is entire S
Dichotomous- 2 Events
mutually exclusive & collectivley exhaustive
S= (on FB, not on FB)
Polytomous- more than 2 events
Suv, sedan, truck, motorcycle
Independent Events
two events are independent if the occurance of one event does not change the probability that the other event will occur
Test for Independence
1) If P(A 1 B) =P(A)
2) If P(A and B)= P(A) P(B)
Marginal Probability
Single Event
P(A)
Joint Probability
2 or more events occuring together
P(A and B)
Conditional Probability
Probability of an event occuring knowing that another event has also occured
P(A 1 B)
About this deck
By: Jackie Livingston
Textbook: Essentials of Statistics for Business and Economics (with CD-ROM)
Created: 2011-02-09
Size: 40 flashcards
Views: 107
Textbook:
Essentials of Statistics for Business and Economics (with CD-ROM)Created: 2011-02-09
Size: 40 flashcards
Views: 107
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
Kathy