Biostatistics III definitions Flashcards
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a random event is something unpredictable
random event
a random variable is a numerical measurement of outcomes of a random event.
Random Variable (RV)
any measurement that can have different values across individuals and can have values that are labels or numbers?
variable
when a RV is equal to a certain value.
event
the likelihood or chance that an event will occur, expressed as a number from 0 to 1.
probablility
gives the probabilities that the variable equals each possible values.
discrete random variable
takes on infinite number of possible values, area under a smooth curve gives the probability.
continuous random variable
this distribution has one mode?
unimodal distribution
this distribution has two modes?
bimodal distribution
name this skewed distribution from the following description?
Tail to the left
Mean
Negative (Left) Skewed Distribution
name this skewed distribution from the following description?
Tail to the right
Mean>Median>Mode
Positive (Right) Skewed Distribution
when the mean is greater than median and mode? this is what type of skewed distribution
positive skewed distribution
when the mean is lesser than median and mode? this is what type of skewed distribution
negative skewed distribution
this type of distribution is commonly used for continuous RVs(e.g., height, weight, blood pressure).
A large number of statistical tests and calculations can be used if the test statistic follows a normal distribution.
normal distribution
what is normal distribution shaped like?
bell shaped curve
this type of distribution is more spread out than the standard normal distribution.
t Distribution
the parameter for certain distributions (such as t, F, and chi-square distribution)
degrees of freedom
for normal distribution what is the term for the following definition?
symmetric and unimodal (bell-shaped)
Shape
for normal distribution what is this definition?
possible values): (-∞,+∞
Support
for normal distribution what is this definition?
μ denotes the mean and 𝜎^2 denotes the variance.
Parameters
for normal distribution what is this definition?
when X is normally distributed with mean μ and variance 𝜎^2, then we write as 𝑋~𝑁 (𝜇, 𝜎^2)
Notation
for normal distribution what is this definition?
if μ=0 and 𝜎^2=1, we have standard normal distribution, written as Z~𝑁 (0,1)
Special cases
for normal distribution, the lower pth percentile for Z is denoted by?
zp.
indicates the value below which a given percentage of observations fall.
percentile
this is the term for the following definition of a binomial distribution property?
Symmetric, Skew Left, Skew Right - depending on the value of parameters
shape
this is the term for the following definition of a binomial distribution property?
(possible values): 0, 1, 2, …, n
support
this is the term for the following definition of a binomial distribution property?
n denotes number of trials and p denotes the probability of “success” on each trial
parameters
this is the term for the following definition of a binomial distribution property?
If X counts the number of successes among n trials where each trial has a probability of “success” equals p, and X is binomially distributed, then we write X ~Bin(n, p)
notation
this is the term for the following definition of a binomial distribution property?
if n=1, we have the Bernoulli distribution and we write X ~ Ber (p)
special cases
