The spreadsheet below shows a list of names with the answer in cell D2. *Ross* is the name that occurs the least in that list.

This formula returns the least frequent value from the list in A2:A16. The formula is explained below so keep reading.

{=INDEX(A2:A16,MATCH(MIN(COUNTIF(A2:A16,A2:A16)),COUNTIF(A2:A16,A2:A16),0))}

This formula is an array formula so you need to press **Ctrl + Shift + Enter**, and not **Enter**. This will put the curly braces around the formula. You do not type these.

Within this formula the COUNTIF functions are used to return how many times each name occurs in the list. The COUNTIF functions return the result below;

{2;5;5;4;4;5;4;4;5;2;4;5;4;4;4}

This means that the name in the first cell of that range (A2) occurs twice, 2nd cell (A3) occurs five times, 3rd cell (A4) occurs five times and so on.

The MIN function returns the smallest number from that array, which is 2 in this example.

The MATCH function is then used to search for the position of the first instance of 2 (the least mentioned names position). The result of this is 1, because the first instance of 2 is in the first cell of range A2:A16.

The INDEX function then returns the value which is in that cell (A2). Which in this example is *Ross*. Watch the video below for a visual explanation of this formula.

The INDEX and MATCH functions are awesome when used together for a flexible lookup formula. Find out more at this INDEX and MATCH tutorial.

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]]>It may be a neat way of deciding who is next to do the washing up, or to make the tea :). Or it is useful for randomly drawing teams for a knockout cup competition.

To perform this random selection, we are going to use two different functions together. They are INDEX and RANDBETWEEN.

The INDEX function is used to return a value from a given cell in a range, and the RANDBETWEEN function is used to calculate a random number between two given numbers.

When used together, we can get the INDEX function to return a value (a persons name) from a random cell within its range.

The following formula has been entered into cell C3 to return a name at random from the list in A2:A13.

=INDEX(A2:A13,RANDBETWEEN(1,12))

The INDEX function used the 12 cells from A2:A13 as its array. The RANDBETWEEN function is then told to generate a random number between 1 and 12 and INDEX returns the value from that cell within its range.

So for example, if RANDBETWEEN returns the number 4, then INDEX returns the name from cell A5.

Want to learn more awesome formulas like this? Check out our Excel Formulas Made Easy online course.

The RANDBETWEEN function is a volatile function. This means that it calculates every time Excel does. Not all functions work this way, and normally only calculate when necessary to do so.

Because of this you may want to switch from automatic calculations to manual, otherwise the formula will constantly generate a random name, and not just when you need one.

To do this, click the **Formulas** tab on the Ribbon, then click **Calculation Options** and then **Manual**.

Now, to run calculations on the worksheet you can press **F9**.

By **adding a scroll bar to the chart**, users can interact with the chart and scroll to see the data they want displayed.

In this example, we have a spreadsheet with revenue for the last 23 months. As this is a lot of data to plot, we have decided that the chart will only display 5 months at a time. A scroll bar will be added so that users can scroll through the years.

The screenshot below shows the 23 months of revenue on the spreadsheet.

Download the spreadsheet to follow along

Our first task will be to create a condensed version of this table only showing the 5 months that the chart will use as its source.

- On a new worksheet, enter 1 in cell A2. The reason for this number will become clearer as we go on. Essentially this value will change as the user scrolls on the chart. It stores the row number of the data to return for the chart.
- Write the following the INDEX function in cell A4.

=INDEX(‘All Data’!$A4:$A$26,Chart!$A$2)

The INDEX function is used in Excel to return a value from a specified row and column. Its syntax is;

=INDEX(*array*, *row_num*, [*column_num*])

In this instance we are using it to return the value from column A that is in the row number stored in cell A2 of the *Chart* sheet.

There is no dollar sign before row 4 in the formula. This is important, as it ensures that when we copy the formula down, the row number will change. All other parts of the reference are fixed.

- Copy the formula down to cell A8.
- Enter the formula below in cell B4.

=INDEX(‘All Data’!$B4:$B$26,Chart!$A$2)

- Copy the formula down to cell B8.

Now that we have the data source, its time to create the chart.

- Select range A3:B8.
- Click the
**Insert**tab,**Line**and select a Line graph. - Perform any formatting options you want for better presentation. In the example below I have removed the Legend, removed the value axis and gridlines, and also added the values as data labels to the chart.

The final stage and the one we have been waiting for is to add the scrollbar to the chart.

- Click the
**Developer**tab on the Ribbon.

**Note:** If the Developer tab is not visible, click **File** > **Options** > **Customize Ribbon** and check the **Developer** box on the right.

- Click the
**Insert**button and select the**Scroll Bar ( Form Control)**from the menu.

- Click and drag to draw the scroll bar onto the worksheet underneath the chart.
- Click on the
**Properties**button on the Developer tab, or right mouse click the scroll bar and select**Format Control**. - The Format Control dialog box opens. Ensure the
**Control**tab is selected. - Enter 1 in the
**Current value**field. - Type 1 for the
**Minimum value**. The lowest row number in the table is number 1. - Enter 19 for the
**Maximum value**. There are 23 months of data. By displaying 5 months on the chart at any time the maximum row number must be 19. - Type 1 for the
**Incremental change**. This is the number of months the chart scrolls when the scroll bar arrow are clicked. - Enter 5 in the
**Page change**field. This is the number of months that the chart scrolls when you click within the scroll bar. - Click in the
**Cell link**field and then select cell A2 on the sheet. The reference $A$2 should appear in the field. This is the cell containing the row number to return for the chart. The scroll bar will change this when used.

- Click
**Ok**.

Click elsewhere on the spreadsheet to make the scroll bar active. Now when used the chart changes the information that is displayed.