# Australian Bureau of Statistics

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 CensusAtSchool Australia

CaSQ 8 - Stem and Leaf Plot of Travel Time

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 How to: Get a Random Sample from CensusAtSchool Go to the CensusAtSchool Random Sampler to download a sample. Reference year: (select year) Sample size: At least 20 students Select questions: Travel time to school Location: Select location Year level: All To protect privacy there is a rule built into the sampler that the requested sample size cannot exceed 10% of the respondents for the parameters entered.

1. In your CensusAtSchool random sample, find the question Travel Time, and record the twenty numbers below.

Outliers are any values which appear to be very different from the majority of the data. They are extreme values and may have been caused by an error. They should be removed from your data set and replaced with the next value from your list.

Think of the numbers in your data set as split into two digits. In a stem and leaf plot, the first digit will be the stem and the second is the leaf. e.g. 21 and 27 have the same stems but different leaves.

2. Circle the stem and underline the leaf for the following numbers 18, 42, 97, 8

3. a) In ascending order, place all the stems in the left column below. There should be no missing stems between your minimum and maximum values even if you have no data that belong in that group. Place each leaf next to its appropriate stem in the first table.
b) In the second table copy the stems and place your leaf values in ascending order.

Travel Time
A stem and leaf plot is not finished until it has a key that explains the value of the numbers.

Key 2 l3 represents 23

4. In another set of data what different number could 2 l3 represent? Explain.