Lecture 8 – Graphs - summary page
-Don’t misrepresent your data by adjusting the scale unless it makes sense (without being
a. They tell you how common certain answers are.
i. “Graphs””Chart Builder” [all graphs created from here]
1. Simple histogram
•Independent variable is always on x axis except in box plot.
•Line in middle ofthraph is median th
•Top of box is 25 percentile, bottom is 75 percentile.
•Line at top is maximum
•Line at bottom is minimum
•SPSS will print out outliers and extreme outliers – cases that are much different than
other scores. If a score is between 1.5 and three box lengths its considered an
outlier. An extreme value is if it is three times the box lengths away, and is
marked with a star. An outlier is marked with a circle.
o Have to know what to do with outliers. Need to first make sure they’re
legitimate scores (a dramatic outlier may be a missing value). They are
also illegitimate if there is a typo in data entry. Or sometimes you have to
do with an outlier that’s an extreme case that skews data. Do you get rid
of them or not, since they are technically a legitimate case?
a. Displays the median, the middle 50% (the “interquartile range”), the range, and
i. Attitudes towards Canadian government by language spoken at home 2
ii. Outliers - in SPSS, scores which are between 1.5 and 3 box lengths