Bar graphs: (Multiple Choice)

Bar graphs:
 
  a. Depict frequency distributions, using bars to show the number or percentage of cases for each category of a variable.
  b. Are best used with ratio level variables.
  c. Contain bars that touch each other.
  d. Have varying distances horizontally between each bar.

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Even if there is some difference in treatment outcome between two groups in our sample, the null hypothesis postulates that the difference can be attributed to sampling error.
 
  Indicate whether the statement is true or false

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The vertical line on a graph:
 
  a. Is called the x-axis.
  b. Never displays the number or percentages of cases for each value of a variable.
  c. Might display different levels of a second variable, thus showing whether changing levels of categories on the variable on the horizontal axis move in a consistent fashion with changing levels of the second variable.
  d. Is always a variable.