Business Analytics Measures of Central Tendency
What happens if an outlier is much larger than the majority of the other data points?
the graph is right skewed
What is the median of the number set: 30.8, 31.7, 30.1, 31.6, 32.1
31.6
What is the notation from median?
M(d)
What is the notation for mode?
M(o)
What are the quartiles?
Q1, Q2, Q3
What are the measures of position?
Quartiles, Percentiles, and Z-Scores
What are the measures of variation?
STD Deviation and Variance; Range and IQR
What is central tendency?
a measure of central tendency represents the center or middle of the data
What is sample statistic?
a number calculated using the sample measurements that describes some aspect of the sample
What is median?
a value such that 50% of all measurements after having been arranged in numerical order, lie above (or below) it positional value not mathmatical
What is normal distribution?
based on mean and standard deviation
Why can graphs be skewed?
because of outliers
What is it called if there are two modes?
bimodal
What happens if an outlier is much smaller than the majority of the other data points?
the graph is left skewed
What is the most common use for mode in a business?
inventory
What is mode?
is the measurements that occur most frequently; values that are observed "most typically"
Why is mode different than median and mean?
it is the only central tendency measure for qualitative data
What is pulled by the outliers?
mean
What are the characteristics of a left skewed graph?
mean < median outliers are in the lower portion of the data set
What are the characteristics of a right skewed graph?
mean > median outliers are in the upper portion of the data set
What are the characteristic of a normal distribution graph?
mean ≈ median
What are the measures of central tendency?
mean, median, mode
What are outliers?
measurements that are very different from other measurements either much larger or much smaller than most other measurements
What are the descriptive statistics used for summary?
measures of central tendency, measures of variation, and measures of postions
What is Q1?
median of the lower half (below the median) of the distribution- 25th percentile
What is Q3?
median of the upper half (above the median) of the distribution- 75th percentile
What is it called if there are three or more modes?
multimodal
What is it called if there are no modes?
no mode
What is this an example of and what will happen to the graph? Most people go the speed limit but some people go 20 or 30 MPH over the speed limit
outliers right skewed
What is the notation of population parameter?
population mean (mu) is average of the population measurements and most of the time is unkown
What is the first thing you should do calculating the median?
put the data set in numerical order
What is the notion of sample statistic?
sample mean √x or √any variable name is the average of the sample data anything with a bar or √ over it is a mean or average
What do you do if the number of measurements is even when measuring median?
the median is the average of the two middlemost measurements in the ordering
What do you do if the number of measurements is odd when measuring median?
the median is the middlemost measurement in the ordering
What is Q2?
the median of the distribution- 50th percentile
What is it called if there is one mode?
unimodal
When can you use mean?
when the median and mean are equal
What do you not use mean?
when there are outliers
How can we describe the data?
with the measures of central tendency