Unit 4: Describing DataUnit 4: Describing Data

After 8 long weeks, we have finally finished Unit 3: Linear & Exponential Functions. Now on to Unit 4 which will last 3 weeks (yes we will finish the week we get back from Thanksgiving). This unit is all about statistics, so let’s begin by getting to know some of the vocabulary of statistics…

Vocabulary:• Box-and-Whisker Plot (Box Plot)• Center • Dot plot• First Quartile • Histogram• Interquartile Range• Mean Absolute Deviation• Outlier• Second Quartile (Q2)

• Shape• Symmetry • Number of Peaks• Direction of Skew• Uniformity• Spread

• Third quartile • Trend• Association• Bivariate data• Categorical variables• Causation• Conditional Relative

Frequencies• Correlation Coefficient• Joint Frequencies• Line of best fit• Marginal Frequencies• Quantitative Variables• Residuals• Scatter plot• Two-frequency table

Learning Target:Learning Target:

Students can identify the best way to represent, compare, and interpret sets of data.Standard: MCC9-12.S.ID.1-3, 5-9, SP.5

Box PlotBox PlotA plot showing the minimum,

maximum, first quartile, median, and third quartile of a data set; the middle 50% of the data is indicated by a box.

Example:

Box Plot: Pros and Box Plot: Pros and ConsCons

Advantages:•Shows 5-point summary and outliers •Easily compares two or more data sets •Handles extremely large data sets easily Disadvantages:•Not as visually appealing as other graphs •Exact values not retained

Dot PlotDot PlotA frequency plot that shows the

number of times a response occurred in a data set, where each data value is represented by a dot.

Example:

Dot Plot: Pros and Dot Plot: Pros and ConsCons

Advantages:•Simple to make•Shows each individual data pointDisadvantages:•Can be time consuming with lots of data points to make•Have to count to get exact total. Fractions of units are hard to display.

HistogramHistogramA frequency plot that shows the

number of times a response or range of responses occurred in a data set.

Example:

Histogram: Pros and Histogram: Pros and ConsCons

Advantages:•Visually strong•Good for determining the shape of the dataDisadvantages:•Cannot read exact values because data is grouped into categories •More difficult to compare two data sets

Histogram vs. Bar Histogram vs. Bar GraphGraph

• Histograms are a great way to show results of continuous data, such as: – weight– height– how much time– etc.• But if your data is in categories

(such as Country or Favorite Movie), then you should use a Bar Graph