data management ch 1.1-1.4 quiz Flashcards
Population:
the entire group of the study
Sample:
a selection of some individuals from the population
cross-sectional:
measured variables at a specific point in time
longitude:
measured variables over a long period of time
raw-data:
unprocessed information collected for a study
variable:
information you are studying which may be different for each person in the study
qualitive variable
cannot be measured numerically
quantitive variable
can be measured numerically
descrete data:
measured with whole numbers
only for quantitive variables
continous data:
measured within a given range
only for quantitive variables
ordinal variable:
can be put into relative order
nominal variable:
categories that cannot be ordered
how to calcualte relative frequencies
frequency / total frequency
how to calculate the angle on a circle graph
multiply the percent by 360
will make an angle
how does the key work in a stem and leaf plot
its a random number with a line splitting the stem and leaf, beside it you would write means [the normal number]
how does the key work in a pictograph
each [picture] represents _% [title]
what are the titles for a frequency table
of _, tally, frequency, cumlative frequency, relative frequency
how to find cumalitive frequency
add frequency with the one/ sum above
how to find relative frequency
frequency / total frequency
what is the difference between bar graphs and histographs
bar graphs use seperate graphs, histograph bars are togethr
what does the bars apart from eachother represent for a bar graph
that there is seperation between the groups
what does the bars touching represent for a histograph
that the bars are continous range of values
REMEMBER there is no interval notation in the x-axis
how do you explain intervals when reffering to a histogram
the [ represents ≤
the ) represents >
how do you calculate the bin width
max value - min value / # of bins
ALWAYS round answer up if there is a decimal
what is a frequency polygon
the same information as a bar graph but simpler to look at
its a line
ogive (cumalitive frequency)
the running total from lowest value up
the cumalative frequency are the y-values
frequency tables for histograms
1. what notation
2. what else is there
3. what if there is a polygon
you have to use interval notation; (there may also be a midpoint which means the meadian of the interval)
if there is a polygon, just draw a line in the middle of the bars
relative frequency polygons
the y-values
the y-values go from 0-1, go up 0.1, 0.2, 0.3
what is the median
the middle value
what is the mode
the most frequent number
what is the median
the average,
add all the numbers together, divide by the total amout of numbers
x-bar formula and what does it mean
the x bar is the sample mean, it calculates the mean
……….Σx
x̄ = ——
……….n
how to calculate the weighted mean
multiply the percent with the ‘mark’ for example
weighted mean formula
………..Σxw
x̄w = ——
………….Σx
remember the denominator will always equal 100%
