Introduction%20to%20Statistics

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Forging new generations of engineers
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Introduction to Statistics
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Statistics Lab
Using Packages of Colored Candies
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Purpose of Statistics
Describe a set of numbers and then make accurate
inferences (a.k.a. educated guesses) about that
group of data based on incomplete information
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Statistics Involves

1. Gathering Data
2. Organizing Data (sometimes pictorially)
3. Analyzing Data

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The Problems

1. Although candies are sold by weight rather than
   volume, how many candies can I expect when I open
   a 1.69 oz package?

2) How likely is it that the numbers of colors in
each package occurred randomly?
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Gathering Data

• Open your package of Candy
• Separate, count and record the number of each
  color in the package.

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Organize the Data

• Open an EXCEL Spreadsheet Document

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Organize the Data
Continue with the entire classs information.
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Analyzing Data problem 1
Although candies are sold by weight rather
than volume, how many candies can I expect when I
open a 1.69 oz package?
What do I need to know?
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Analyzing Data
Measures of Central Tendency
Mean
Average
Median
Number in the Middle
Mode
Number used Most
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Analyzing Data
Measures of Variability
Range
Spread
Standard Deviation
The average distance each piece of
data is from the mean
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Analyzing Data
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Analyzing Data
Use the Insert gt Function capabilities of Excel
to do the calculations
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Analyzing Data
What do each of these calculations mean?

1. Supposed I only get 22 candies. Am I being
   cheated in quantity?

2) How about 74 candies?
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Analyzing Data problem 2
How likely is it that the numbers of colors in
each package occurred randomly?
How can I test this?
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Analyzing Data using an EXCEL function
ChiTest A test for independence which returns the
probability that your observed data and your
expected data are related.
In this case we are seeking an answer to How
likely is it that the candies counted were
packaged strictly by chance?
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Analyzing Data
Hypothesis The observed number of colored
candies per package is not significantly
different than the number found if the candies
were packaged purely at random.
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Analyzing Data
The CHITEST returns a value between 0 and 1. The
closer the number is to 1, the more likely your
hypothesis is true.
Back to EXCEL
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Analyzing Data
Use EXCEL CHITEST function to determine the
probability that your bag of candies were
packaged according to these percentages.