Center
-average
-indicates the middle of data location
variation
measure amount the values vary
distribution
shape of data (bell, skewed)
outliers
values that lie far from majority
time
changing data over time
explain stem plot and how to use
-good for small data
-stem= beginning number
-leaf=end number
-eg- 12= 1|2
-majority will be most recurring
stem
-write numbers that arent included still
for side by side:
-use same stem
-right side will go larg-smallest
-left side will go smallest-larg
for graphs, what is x line and what is y line
x- data points
y-frequency
Relative Frequency
-equal to freq divided by total data
-f= freq
- n= total data
-RF= f/N
median formula
(n+1)/2
-n total number of values
-if whole keep as answer
-location
-small to largest
-if your answer is with .5, you need to add the two numbers and divide by 2
quartiles
-special percentiles
-Q1 is 25th
-Q2 is 50th (also median location)
-Q3 is 75th
-data needs to be smallest to largest
Interquartile Range
IQR=Q3-Q1
outliers and method for finding it
value that is way larger or smaller than the other data
-find Q1 and Q3
-find IQR
-lower outlier= Q1-1.5(IQR)
-upper outlier=Q3+1.5(IQR)
-if data is less then Q1 and higher than Q3 then its an outlier
Finding data from percentiles
-smallest to largest
-i=k/100(n+1)
-k is the percentile (eg 28th)
-i is the location in data
-n is number of data
-if number has decimal eg 3.36 location will be between 3rd and 4th number…. add them/2
finding percentiles from data
-smallest to largest
-round to nearest whole
-(x+05y)/n (100)
-x is the number of data before your percentile you want to find
-y is how many of that number is there
five number summary
Minimum data value
Q1
Median
Q3
Maximum data value
-used for box plots
Box plots
-draw a line with smallest and largest data at endpoints
-add your Q1 median and Q3
-the box will be the length of Q1 to Q3
-add whiskers from min to max values
-may need to find 25th and 75th percentiles
see slide 40 to go over
measures to find the center
median
mode (easier)
sample mean
-x bar
-add all sample sizes together and divide by n
population mean
-mew U
-add all sample sizes together and divide by n
mode
most frequent value
-two modes are called bimodal
In a symmetrical distribution that has two modes
(bimodal), the two modes would be _________ from the
mean and median.
different
symmetric histogram
will have mean med and mode with the same or very close values
skewed to the left
-smaller on left side
-larger numbers are more recurring
-mean<med<mode
< vs >
< less
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