Exam 1 Flashcards
what is the formula for union probability?
P(A or B)=P(A)+ P(B)-P(A and B)
what is the formula for complement probability?
P(A^C)=1-P(A)
P(A^C)=complement of A
what is the conditional probability rule
P(A and B)/P(B)
what does sensitivity mean?
true positive and have disease; yes yes
what does specificity mean?
true negative and do not have disease; no no
what is the parameters for binomial distribution?
X(squiggly line)Bin(n= ,p= )
what is the parameters for normal distribution?
X(squiggly line)N(mean= , std. dev.= )
what are the appropriate graphs for quantitative (discrete or continuous) data?
histograms, box plots, or dot plots
what are the appropriate graphs for categorical data?
pie chart, Pareto chart, or bar chart
explain SOCS
Shape-skewness, modality
Outliers-how many, high/low
Center-depends on skewness and outliers, mean or median
Spread-depends on skewness and outliers, std. dev. or IQR
what signifies a strong correlation?
.7+
what signifies a moderate correlation?
.4-.6
what signifies a weak correlation?
.1-.3
examples of variability in the real world (3)
gas prices, heights, temperatures
what are the 3 main reasons to study statistics?
-being informed
-making good decisions
-evaluating those decisions
where do we find statistics? (4)
news, articles, surveys, charts/graphs
in statistics, ____________ provides meaning to our studies
context
what are the 2 ways stats differs from math?
role of context and logic of statistical inference
the total set of all “individuals” of interest
population
a subset of “individuals” selected from the population
sample
numerical characteristic of a population, a fixed quantity; one, set value(typically unknown)
parameter
numerical characteristic of a sample, a variable quantity; every new sample creates a new _____________
statistic
match these:
population sample
statistic parameter
population–>parameter
sample–>statistic
what 3 things should you be able to identify in a statistical question?
-the population being studied
-the variable(characteristic) to be measured
-the variation that may occur in the measurement of that characteristic
what are the 4 steps in solving a statistical problem?
-formulate a statistical question
-collect data
-analyze data
-interpret and communicate results
methods for organizing data; summaries, reports, records
descriptive statistics
methods for drawing conclusions about a population; predict, estimate, conclude, infer
inferential statistics
a list of distinct categories and their counts
frequency distribution
a list of distinct values and their relative frequencies (proportions/percentages)
relative frequency distribution
how is relative frequency found?
taking the frequency for that category and dividing it by the sample size
what are the 2 numerical summaries for categorical data?
frequency distribution and relative frequency distribution
what methods are used to describe quantitative data? (3)
SOCS, scatterplot, contingency table
what is the law of large numbers?
the probability of an event is the proportion of times it occurs in a large number of repetitions of the experiment
the more times we do an experiment, the closer our experimental probability will become to our theoretical probability
probability based on personal opinion
subjective probability
probability based on formulas
theoretical probability
probability based on results of a random experiment
experimental probability
events that have no outcomes in common
mutually exclusive
the occurrence of one event has no effect on the other event
independent
individual event probability
marginal probability
probability of the overall sample
unconditional probability
probability that’s conditioning on an event
conditional probability
how do you verify if something is a valid probability distribution?
add up all probabilities and verify that they equal 1 exactly
what are the 4 binomial conditions?
1) fixed # of trials, n=
2) 2 possible outcomes, success/fail
3) probability of success is the same? p=
4) independent
