Exploring Computer Science Lesson 5-9 Statistical Measures Exploring Computer Science Lesson 5-9

Objectives The students will be able to: • Read and interpret a histogram. • Create a histogram. • Read and interpret a box plot. • Create box plots. • Explain mean, median, minimum, maximum. • Create and query subsets of a data set.

Journal Entry Thinking back to pivot tables and pivot charts, why are we making graphical representations of our data instead of just using the numbers? Are there advantages to the different representations of data?

Histograms A Histogram is a graphical display of data using bars of different heights. It is similar to a Bar Chart, but a histogram groups numbers into ranges And you decide what ranges to use!

Histograms The horizontal axis is continuous like a number line Histograms are a great way to show results of continuous data, such as: weight height how much time etc.

Sleep Chart How much sleep did you get last night?

Analyzing Data from the CDC Download the file CDCRDA.csv from the homework section. How many people are included in this data file?

Getting Subsets of Data What if I didn’t want to analyze the data for all the people? What if I just wanted to analyze data for the freshman? In Excel we can use filters to get the lines we want. On the Home ribbon, click on Sort & Filter and Filter:

Filters You use drop downs on the headers that allow you select just the data you want. I want just 9th grade. Result:

Filters To analyze just this data you need to copy and paste it to a new sheet. Cntl-Shift-8 (Cntl-*) selects all the data. Copy (Cntl-c) Click on a new sheet Paste (Cntl-v)

Excel - Formulas All formulas begin with an equal sign “=“ All formulas have a number or cell reference and an operator Examples: =A1 + C2 =5 + 7 =A17 + 14 When using a cell reference, the cell must contain a number!

Excel: Formulas Basic Operations: Operator Operation Meaning + Addition Adds the values - Subtraction Subtracts the values * Multiplication Multiplies the values / Division Divides the values % Percentage Calculates % of a value

Excel: Formulas Examples:

Data Analysis Functions in Excel Sum Mean (Average) Median (The number in the middle of the list)

Excel: Functions Functions are predefined formulas that work on a range of data Functions perform formulas in a quick and easy way. You could type a formula to get the same result but it would be difficult to type and extremely difficult to maintain.

Excel: Common Functions Formula Meaning SUM =SUM(A2:F5) Adds the cells from A2 though F5 AVERAGE =AVERAGE(A2:F5) Finds the average of all the cells from A2 through F5 MIN =MIN(A2:F5) Finds the smallest number in cells A2 through F5 MAX =MAX(A2:F5) Finds the largest number in cells A2 through A5 MEDIAN =MEDIAN(A2:F5) Finds the number in the middle of a set of numbers. If there is an even number of numbers in the set, then MEDIAN calculates the average of the two numbers in the middle

Excel: SUM Ranges for SUM can include cells that have text in them. If a cell does not contain a number it is simply skipped.

Excel: AVERAGE Like SUM the range can include non- numbers and those cells are skipped.

Excel: MEDIAN Like SUM the range can include non- numbers and those cells are skipped.

You Need Data by Next Time! Get people to take the class survey! If you don’t have data for your research question you will be trying to find some online. You will not just make it up!

Back to that CDC Data… Download the file “Lesson 5-9 – Homework.docx” from homework section. Answer all the questions or copy charts, etc into the word doc. Print it out and turn it in before you leave today!