objectives c3 Flashcards
nominal grouping
categorizing in a mutual charateristic
ordinal
ranked positions
continuous
numbers that occupy a distinct place on a number line. It can be an interval or ratio in form
interval
an equal or common unit of measurement, and it has a value of zero that simply represents a number on a point of a number line. an examle is having zero on the centirgrade scale which does not mean the absence of heat but the temp in which water freeze.
ratio
same as interval but have a true zero like weight, time, and kelvin (0Kabsolute lowest temp.)
list the scales of measurement are hierarchical in that each builds on the previous levels
nominal-ordinal-interval-ratio
summation notation
sum of all X values is equal to sigma (sum up)
frequency distribution
is a method of organzing data that involves nothing the frequency with which various scores occur.
a method in comparing others performance
percentile
represents the percent of observations at or below a given score
central tendency
tend to center
what are the 3 measures of central tendency
mean, median, mode
mean
sum of scores divided by the number of scores
median
middle score; 50th percentile, obtain the median, order the scores from high to low and find the middle one
mode
most unstable measure and the msot requently observed score
why does only observing the distibution’s measures of central tendency no tell you everything about the scores?
not all distributions have the same shape
skewness
statistical term for shape (symmetry) of a distribution
ranges from +1 to -1
identify the locations of the measures of central tendencies on a skewed distribution
mean generally closest to the tail
highest point is the mode
median btw mean and mode’s locations
kurtosis
the peakness of the curve
mesokutric
normal bell shaped
platykurtic
flatter
leptokurtic
narrow curve
histogram
is a graph that consists of columns to represent the frequencies with which various scores are observed in the data
what type of kurtosis shape has more homeogenous varibality data and heterogenous (dissimliar) data
platykurtic-heterogenous dissimilar data
leptokurtic-homeogenous data (sIMILAR)
variability
Variability refers to how spread out the values in a data set are. It measures the degree to which data points differ from each other and from the average (mean). High variability means data points are spread out widely, while low variability indicates they are clustered close together.
what are the 3 measures of variability
range, variance, and standard deviaition
range
highest score - loweest score
variance
is a measure of the spread of a set of scores based on the squared deviation of each score from the mean.
most stable measure of variabitly
what happens when all scores are identical
variance is zero
don’t want bc no variabilty means no measure
standard deviation
square root of the variance
linear measure of variabiltiy that helps identify heterogentiy and homeogenity of scores
normal distribution
bell shaped symemtirc distibution
why is the standard score in a normal distribution so important
regardless of the mean and standard deviation are as long as the distibution is normal then the standard deviations will tell a great deal about the probability distibution
tell me the standard deviations in a normal distribution
M+1= 88.26%
M+2=95.44%
M=3=99.74%
A standard score, or z-score
tells you how far a specific data point is from the average (mean) of a group of values, but it measures this in terms of standard deviations. This way, you can see if a value is higher or lower than average and by how much.
t/f: z sccores always have a standard deviation equal to 0 to 1.
tru
what can z scores determine (standsrd scores)
determination of percentiles
percentage of observations that fall withina particular area under the normal distribution
