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Why Error Checking is Important
3:04 with Tyler TallonNow let's learn about the importance of error checking and look at some effective ways to check your work.
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Please note that this is a new spreadsheet, different from the one you used in the previous stage:

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[MUSIC]

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So far in this course we've learned how to use look up functions,

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create a pivot table, and learned how to use several other tools in Excel.

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Now we're going to learn about the importance of error checking,

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which has saved me so many times.

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And I'm excited to show you some effective ways to check your work.

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Before we dive in to the error checking process,

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let's first discuss some common errors in Excel.

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Generally, there are four different types of errors.

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Input errors, which are data entry errors or missed data.

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Output errors, usually caused by incorrect cell referencing, problems with time or

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date switches or graphic outputs not updating properly.

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Conceptual logic or using the wrong formula.

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And then formula errors, which could be using the correct formula but

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typing it incorrectly, or the wrong order, or

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incorrect parenthesis, basically just bad math.

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Let's drill down a little further on some of these errors by looking at

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a few examples on our spreadsheet.

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First, let's look at a common error that can come from adding rows.

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Here we have store sales by state in month for the first half of the year.

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Let's say we want to say a sum to get the total at the bottom.

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Let's sum each month by using the AutoSum feature up at the top right.

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And then let's copy this over for each month.

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Okay, now let's add a row to our data.

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For newer worksheet versions like I'm using, if you add

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a row in the middle of your data, then the sum range will automatically update.

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You can see this by double clicking on the sum row, and

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a box will appear around the group of cells that it's summing.

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It's always good to double check this when you add rows.

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But now let's try adding a row at the top.

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If I add a row here, And then doubleclick on this sum row,

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you'll notice that the top row is not included in my sum.

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So if I were adding data for Alabama here,

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You'll see it's not included in the sum.

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To correct this, you can just change the formula to start at B2 instead of B3.

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Now you can see it's including every state.

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And then you'll want to make sure to copy that formula over to the remaining months.

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Now just to make sure it copied correctly, let's doubleclick on June's total.

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Yep, looks like I copied over correctly.

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Coming up, we'll keep looking at some common errors and

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learn about how to avoid them.
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