Ratios & Percents To help us understand the data, calculate ratios for: –Infected to uninfected –Infected to total –Uninfected to total Use those ratios to create percents for each of the three values Make sure you write down what the numbers are in your journal Do it neatly, so you can come back to it tomorrow & Friday and know exactly what those numbers are, how you calculated them, and what they mean.

Mean, Median, Mode, and Range

New Objectives! Content Objectives SWD understanding of central tendency by calculating mean, median and mode of shrimp data set. Language Objectives SWD evaluation of central tendency by creating a graph comparing data sets.

Vocabulary mean median mode range outlier Insert Lesson Title Here

Measure of central tendency are used to describe the middle of a data set. Mean, median, and mode are measures of Central Tendency.

An outlier is a value that is either far less than or far greater than the rest of the values in the data.

21, 21, 28, 29, 30, 28, 32 mean: = 189 Add the values. Divide by 7, the number of values = 27 median: Order the values. mode: Two values occur twice. The median is , 28 Find the mean, median and the mode of the data set. range: 32 – 21 = 11

45, 32, 22, 37, 45, 41, 37 mean: = 259 Add the values. Divide by 7, the number of values = 37 median: Order the values. mode: Two values occur twice. The median is , 45 Find the mean, median and the mode of the data set. range: 45 – 22 = 23

When is one measure more appropriate or more useful than another? When data are in categories, mode can be very helpful & representative Mean is best for continuous data (not categories), like rainfall Outliers affect mean, so median is often used when outliers are present –Example: salary & financial data

When is one measure more appropriate or more useful than another? Look over the shrimp data –Calculate mean –Find median –Find mode(s) –Find range Which one do you think represents the data better, and why? Are there outliers? If so, which measures do they affect the most?

Prep for tomorrow How do you find the percent of something? What kinds of graphs can you create with the data?