SHAPES OF HISTOGRAMS

A graph formed by joining the midpoints of the tops of successive bars in a histogram with straight lines is called a polygon.

In a stem-and-leaf display of qualitative data, each value is divided into two portions: a stem and a lea

One of the simplest methods for graphing and understanding quantitative data is to create a dotplot.

Dotplots can help us detect outliers (extreme values) in a data set.

An advantage of a stem-and-leaf display over a frequency distribution is that by preparing a stem-and-leaf display we do lose information on individual observations

Data sets consist of measurements collected over time at regular intervals so that we can learn about change over time

A time-series plot can be constructed by thinking of the data set as a Trivariate data set

are presented in the form of a frequency distribution table.

Ungrouped data: data that gives information on each member of the population or sample individually.

Mean for population data:

mean =

the value of the sample mean 𝑥 varies from sample to sample

Sometimes a data set may contain a few very small or a few very large values. Such values are called

The mean is always the best measure of central tendency because it is heavily influenced by outliers.

The ......... is the value of the middle term in a data set that has been ranked in increasing order

sample median : The single middle value if 𝑛 is ........

median =

The mode is the value that occurs with the highest frequency in a data set.