Lecture 6 Flashcards
The normal distribution is sometimes called the
BELL CURVE
The normal distribution is also known as the
GAUSSIAN DISTRIBUTION
Who is the German mathematician who first described the normal distribution?
Carl Friedrich Gauss
It is a probability function that describes how
the values of a variable are distributed
NORMAL DISTRIBUTION
The red curve is a model called the
NORMAL CURVE
a variable that can take on an infinite number of values within a specific interval
CONTINUOUS RANDOM VARIABLE
Other term for normally distributed
NORMAL PROBABILITY DISTRIBUTION
A normal random variable having mean = 0, and standard deviation = 1
STANDARD NORMAL RANDOM VARIABLE
What do you call the density curve of the standard normal random variable?
STANDARD NORMAL CURVE
The normal random variable of a standard normal distribution is called a
STANDARD SCORE / Z-SCORE
is a family of distributions that look
almost identical to the normal distribution curve, only a bit shorter and fatter
T-DISTRIBUTION / STUDENT’S T-DISTRIBUTION
number of values in the final calculation of a statistic that are free to vary
DEGREES OF FREEDOM
s the average of the given numbers and is calculated by dividing the sum of given numbers by the total number of numbers
MEAN
measure of the amount of variation of the values of a variable about its mean
STANDARD DEVIATION
It is the process of generalizing
information obtained from a sample to a
population
INFERENTIAL STATISTICS
Sample data are used to estimate the value
of unknown parameters such as μ or σ.
ESTIMATION
single points that
are used to infer parameters directly
POINT ESTIMATION
also called
confidence interval for parameter
INTERVAL ESTIMATION
provides more information than point estimates and it consist of an interval of numbers
CONFIDENCE INTERVAL
presents the expected proportion of intervals that will contain the parameter if a large number of different samples is obtained
LEVEL OF CONFIDENCE
is a procedure on sample evidence and probability, used to test claims regarding a characteristic of one or more populations
HYPOTHESIS TESTING
A statement or claim regarding a characteristic of one or more populations
HYPOTHESIS
Assumed true until evidence indicates otherwise
NULL HYPOTHESIS
Sometimes referred to as the research hypothesis
ALTERNATIVE HYPOTHESIS
results from an alternative hypothesis which specifies a direction
ONE-TAILED TEST
will test both if the mean is significantly greater than x and if the mean significantly less than x
TWO-TAILED TEST
the probability of rejecting a null hypothesis when it is true
ALPHA LEVEL / SIGNIFICANCE LEVEL
a false positive that occurs when a researcher rejects a true null hypothesis
TYPE I ERROR
occurs when a researcher fails to reject the null hypothesis when it is false
TYPE II ERROR
is a branch of statistics which leverages models based on a fixed set of parameters
PARAMETRIC STATISTICS
does not make any assumptions and measures the central tendency with the median value
NON-PARAMETRIC STATISTICS
is the set of all values of the test statistic which will lead to the rejection of null hypothesis
CRITICAL REGION
is the set of all values of the test statistic that
leads the researcher to retain null hypothesis
ACCEPTANCE REGION
