Making Tables

1
Making Tables

• The data must be entered first into the TI
  calculator and sorted.

2
Data Ages of Stowaways on the Queen Mary West
Bound
3
The Statistics Mode of the TI

• Press STAT

4
Entering the lists

• Press Enter

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Type in the data

• Type each number, pressing enter after each one

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Sort the data

• Press Stat, 2

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Specify the list

• Press L1 (2nd, 1) and then enter

8
Look at the list again

• Press STAT, Edit, 1

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Classes or groups

• Data is normally divided into 5 to 20 groups,
  called classes. The number of classes depends on
  the amount of data.
• The first and the last class may not have a
  frequency of zero.
• Classes must be mutually exclusive no
  overlapping.

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• All classes must have the same width.
• The classes must be able to include all data
  values.
• Classes can be formed by a natural method. The
  data for the ages of stowaways would naturally go
  from 10 to 19, 20 to 29, etc

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Setting up classes
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Class limits

• The lower class limit is the smallest value that
  could be in a class.
• Lower class limits _____________________________
• The upper class limit is the largest value that
  could be in a class.
• Upper class limits _____________________________

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Class width

• The difference between 2 consecutive lower class
  limits or 2 consecutive upper class limits is the
  class width.
• Class width _________

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Frequency

• Count the number of data values that fall within
  each class to get the frequency.
• The total of the frequency numbers must equal the
  total number of data items.

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The completed table
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Relative frequency

• To find the relative frequency, divide the
  frequency values by the total frequency.
• Write answers as 3 place decimals.
• The total should be 1.000 but sometimes, due to
  rounding, we might get 0.999 or 1.001.

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Relative Frequency table
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Class midpoints

• Class midpoints are found by adding the lower and
  upper class limits together. Divide by 2.
• Class midpoints ________________________________

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Class Boundaries

• Class boundaries separate classes.
• To form class boundaries, add the upper class
  limit of the first class and the lower class
  limit of the second class. Divide by 2.
• Class boundaries ______________________________

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Preparing for a new table

• We will need an invisible class boundary that
  will be before our first real class.
• To obtain it, subtract the class width from the
  first class boundary found.

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Cumulative frequency table
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Cumulative frequency

• Cumulative means to accumulate or add
  frequencies.
• The first cumulative frequency will always be
  zero.
• The second cumulative frequency will always be
  the first class frequency.

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Additional cumulative frequencies

• To obtain the rest of the cumulative frequencies,
  we add the frequency of each class to our
  cumulative frequencies.

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Relative Cumulative Frequency

• To obtain the relative cumulative frequency
  values, divide each cumulative frequency by the
  total number of data values. Write as 3 place
  decimals.

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Relative Cumulative Frequency
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What happens if the data doesnt fall in natural
classes?

• We find a class width by subtracting the highest
  data value and the lowest data value. Divide by
  the number of classes desired.
• We always need to round the answer up.
• Match the number of decimal places in the data.

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Example

• Data set for the weights of quarters.
• Lowest value 5.49
• Highest value 5.84
• Number of classes 5
• (5.84-5.49)/5 0.07
• Class width 0.08 (round UP)

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Classes

• First class lower limit 5.49
• Second class lower limit is 5.49 0.08 or 5.57
• Other lower limits 5.65, 5.73,5.81
• Upper class limits are 5.56, 5.64, 5.72, 5.80,
  5.88