the iPad version. You use the iPad camera to take a picture of a data table that appears on a printed page and then, through the magic of OCR (optical character recognition), Excel extracts the data in the picture and puts it into a spreadsheet.
To start collecting data, follow these steps on your iPad:
1 Find a printed page that presents a data table.For this exercise, I use Table 14-2 of this book.
2 Flatten out the page as much as possible.This increases the OCR’s accuracy.
3 Select a cell in the spreadsheet where you want the data table to begin.
4 Choose Insert | Data from Picture to activate the iPad camera.
5 Take a picture of the data table. Important advice: I hold the iPad in Portrait mode so that the white button is at the bottom of the screen. If I hold it in Landscape mode (which is probably the way you hold your iPad when you use it for Excel), I end up with gobbledygook. Trust me on this one.
6 Adjust the white rectangle to crop out everything but the data.This table has some statistics calculated in the bottom rows. In this example, I crop out those rows and then recalculate the statistics after the data are in the spreadsheet. It’s a helpful check on the accuracy of the OCR — if the recalculated statistics don’t match up with the printed version, something is obviously amiss.
7 Tap Confirm.After a few seconds, the image of the table appears in the upper half of the screen; and the data as it will appear in Excel, in the lower half. Figure 2-33 shows the inaccuracy of the OCR with respect to decimals. You can tap the X in the upper left corner to discard the picture and start again, if you like.FIGURE 2-33: An intermediate result of Data from Picture: The image of the data and the data as it will appear in Excel.
8 When you’re satisfied with the data table, tap Insert.If the accuracy isn’t perfect (and it rarely is), two buttons appear — one labeled Open Anyway and one labeled Review. Review is more of a hassle than it’s worth — it’s easier to review and make corrections after the numbers are in the spreadsheet. (See Step 9.) My rule of thumb: If the cells are properly aligned and most of the data looks okay, tap Open Anyway to put the data in the spreadsheet. If not, tap the X in the upper left corner and restart the procedure.
9 Compare the data in the spreadsheet with the data on the printed page. Correct as necessary.Do not omit this step. I pay close attention to decimals because the OCR sometimes misses the decimal point. As I point out in Step 5, recalculating statistics is a helpful check of the OCR accuracy.
In the Mac version of Data from Picture, you take the picture with an iPhone configured to use Continuity Camera; the option is called Picture from Clipboard. The Mac also gives you the option to choose a picture from your files.
Part 2
Describing Data
IN THIS PART …
Summarize and describe data
Work with Excel graphics
Determine central tendency and variability
Work with standard scores
Understand and visualize normal distributions
Chapter 3
Show-and-Tell: Graphing Data
IN THIS CHAPTER
The visual presentation of data is extremely important in statistics. Visual presentation enables you to discern relationships and trends you might not see if you look only at numbers. Visual presentation helps in another way: It’s valuable for presenting ideas to groups and making them understand your point of view.
Graphs come in many varieties. In this chapter, I explore the types of graphs you use in statistics and explain when it’s advisable to use them. I also show you how to use Excel to create those graphs.
Why Use Graphs?
Suppose you have to make a pitch to a Congressional committee about commercial space revenues in the early 1990s.
Which would you rather present: the data in Table 3-1 or the graph in Figure 3-1, which shows the same data? (The data, by the way, is from the US Department of Commerce, via the Statistical Abstract of the US.)
TABLE 3-1 US Commercial Space Revenues 1990–1994 (in Millions of Dollars)
| Industry | 1990 | 1991 | 1992 | 1993 | 1994 |
|---|---|---|---|---|---|
| Commercial Satellites Delivered | 1,000 | 1,300 | 1,300 | 1,100 | 1,400 |
| Satellite Services | 800 | 1,200 | 1,500 | 1,850 | 2,330 |
| Satellite Ground Equipment | 860 | 1,300 | 1,400 | 1,600 | 1,970 |
| Commercial Launches | 570 | 380 | 450 | 465 | 580 |
| Remote Sensing Data | 155 | 190 | 210 | 250 | 300 |
| Commercial R&D Infrastructure | 0 | 0 | 0 | 30 | 60 |
