chapt.2

• What is a database?

  Tables with a collection of data
• Why are databases considered secondary data?

  They are available online and easily accessible
• What should you do when asked to interpret data from tables in an exam?

  Identify trends and calculate totals
• What is a common inconsistency found in data tables?

  Percentages do not add up to 100%
• Why might percentages in tables not add up to 100%?

  Due to rounding errors in calculations
• How should you think about data in tables during an exam?

  In terms of real-life situations affecting data
• What type of data do two-way tables contain?

  Bivariate data with two variables
• How do you find missing values in a two-way table?

  Start with the row or column with one missing value
• What should you compare when analyzing two-way tables?

  Comparisons between rows, columns, and individual cells
• What do pictograms use to represent data?

  Pictures or symbols
• What is essential to include when drawing a pictogram?

  A key to show the amount each symbol represents
• What must be ensured when drawing symbols in a pictogram?

  Each symbol is the same size
• How should symbols in a pictogram represent numbers?

  They should represent numbers that can be easily divided
• What is a simple bar chart characterized by?

  Equal width bars and equal gaps between bars
• What does a vertical line graph resemble?

  A simple bar chart but with lines instead of bars
• What is the purpose of multiple bar charts?

  To compare two or more sets of data
• What do composite bar charts represent?

  Single bars split into different sections for categories
• How do you calculate the frequency of each component in a composite bar chart?

  Subtract the upper frequency from the lower frequency
• What do stem and leaf diagrams help organize?

  Data without losing any detail
• How are values represented in a stem and leaf diagram?

  Each value is split into a 'stem' and 'leaf'
• What is the first step in drawing a stem and leaf diagram?

  Put the first digits of each data piece in order
• What should leaves in a stem and leaf diagram be written in?

  Order from smallest to largest
• What do back-to-back stem and leaf diagrams show?

  Two sets of data sharing the same stem
• What does a pie chart display?

  How something is shared into categories
• How do you calculate the angle for each frequency in a pie chart?

  Multiply by the frequency and divide by total
• What should you ensure when drawing a pie chart?

  All angles add up to 360°
• What do comparative pie charts compare?

  Two sets of data of different sizes
• Why should pie charts be drawn in different sizes?

  To avoid misleading representations of data
• How do you work out the radius of a second pie chart?

  Divide areas, square root, then multiply
• What does a population pyramid show?

  Distribution of ages in a population
• What does a pyramid shape in a population pyramid indicate?

  A higher proportion of younger people
• What does an upside-down pyramid indicate in a population pyramid?

  A larger proportion of older people
• What do choropleth maps use to represent data?

  Shading of geographical areas
• What does darker shading on a choropleth map indicate?

  A higher frequency for that area
• What is cumulative frequency?

  A running total of frequencies
• How do you calculate cumulative frequency for a class interval?

  Add frequency for that interval to previous CF
• What is the purpose of CF step polygons?

  Used for discrete data representation
• What do CF curves represent?

  Grouped continuous data
• How do you estimate the median from CF diagrams?

  Find the value at total frequency divided by 2
• What is the interquartile range (IQR)?

  Difference between 75% and 25% values