Elementary Statistics Chapter 3 – Study Guide, Key Concepts &
Practice Questions
Statistic - ANS ✔✔Characteristic or measure obtained by using the data values from a sample.
Parameter - ANS ✔✔Characteristic or measure obtained by using all the data values for a
specific population.
Traditional Statistics - ANS ✔✔-Average
-Variation
-Position
Measures of Central Tendency (Average) - ANS ✔✔Mean, Median, Mode, Midrange, Weighted
Mean
Mean - ANS ✔✔Quotient of sum of values and the total number of values
Xs - ANS ✔✔Statistic
Greek Symbol Mu - ANS ✔✔Parameter
Median (Md) - ANS ✔✔Midpoint of data array. (Average in terms of location).
Steps to Finding Median - ANS ✔✔1) Arrange data values in ascending order.
2) Determine number of values in data set.
3) If n is odd, select middle data value as median. If n is even, find the mean of the two middle
values. Add and divide the sum by 2.
, Mode - ANS ✔✔Value that occurs most often in data set.
Unimodal - ANS ✔✔One Mode
Bimodal - ANS ✔✔Two modes
Multimodal - ANS ✔✔Many Modes
Midrange - ANS ✔✔Average of lowest and highest values in a data set.
Weighted Mean - ANS ✔✔Multiply each value by its corresponding weight and divide the sum
of the products by the sum of the weights.
Properties of Mean - ANS ✔✔-Found by using all values of data.
-Varies less than median or mode.
-Used in computing other statistics, such as variance.
-Unique, usually not one of data values.
-Cannot be used with open-ended classes.
-Affected by extremely high or low values, called outliers.
Properties of Median - ANS ✔✔-Gives midpoint
-Used when necessary to find out whether data values fall into upper half or lower half of
distribution.
-Can be used for open-ended distribution.
-Affected less than the mean by extremely high or extremely low values.
Practice Questions
Statistic - ANS ✔✔Characteristic or measure obtained by using the data values from a sample.
Parameter - ANS ✔✔Characteristic or measure obtained by using all the data values for a
specific population.
Traditional Statistics - ANS ✔✔-Average
-Variation
-Position
Measures of Central Tendency (Average) - ANS ✔✔Mean, Median, Mode, Midrange, Weighted
Mean
Mean - ANS ✔✔Quotient of sum of values and the total number of values
Xs - ANS ✔✔Statistic
Greek Symbol Mu - ANS ✔✔Parameter
Median (Md) - ANS ✔✔Midpoint of data array. (Average in terms of location).
Steps to Finding Median - ANS ✔✔1) Arrange data values in ascending order.
2) Determine number of values in data set.
3) If n is odd, select middle data value as median. If n is even, find the mean of the two middle
values. Add and divide the sum by 2.
, Mode - ANS ✔✔Value that occurs most often in data set.
Unimodal - ANS ✔✔One Mode
Bimodal - ANS ✔✔Two modes
Multimodal - ANS ✔✔Many Modes
Midrange - ANS ✔✔Average of lowest and highest values in a data set.
Weighted Mean - ANS ✔✔Multiply each value by its corresponding weight and divide the sum
of the products by the sum of the weights.
Properties of Mean - ANS ✔✔-Found by using all values of data.
-Varies less than median or mode.
-Used in computing other statistics, such as variance.
-Unique, usually not one of data values.
-Cannot be used with open-ended classes.
-Affected by extremely high or low values, called outliers.
Properties of Median - ANS ✔✔-Gives midpoint
-Used when necessary to find out whether data values fall into upper half or lower half of
distribution.
-Can be used for open-ended distribution.
-Affected less than the mean by extremely high or extremely low values.
