Excel Simple Graph Problem - Vista?

Question

I have plotted a graph on vista with x and y variables.

The variable on y is velocity and the x variable is depth.

Rather than both axis being in ascending order what excel is doing is that it is categorising the graph and so the depth values are not in ascending orders and just match site number.

For example the first x value is 187 then 196 then 180 etc.

How can i make it so they ascend?

Answer 1

Because you have mentioned Vista, I am assuming you have 2007 Excel, though it doesn't necessarly follow. When you talk about values on the x axis do you mean the values taken from the spreadsheet data on which the graph is taken or are you referring to the scale? If it is the data, then the graph can only work on the order in which you present your data. If it is the scale,, assuming you are 2007, right button of mouse on the axis scale down to format axis and then you can enter new minimum and maximum levels to the scale. However I suspect from the way your question is worded that it is the actual values and as I say, you will have to change the order of your spreadsheet (using sort) if you want the graph to display the values in ascending order.



If you are not 2007, then its simply double clicking on the axis scale then click on the scale tab and again change min and max.

Answer 2

I suspect you have used the wrong type of graph. What Excel calls a "line graph" is actually a bar chart without the bars and a line connecting the tops of the bars, so that Excel is treating your x variables as a category label not as a number. If so, you will see that the tick marks fall between the x variables and are not centred on them, and that the x variables are not what you would expect - i.e. either not ordered, or not evenly spaced. Also, typically you will see that the x variable value labels are vertical or angled instead of normal.



If this is the cause of the problem, sorting the data will not fix it for you, although it will make the effects less noticeable. Excel does not require the data to be in order for it to plot a proper x-y graph.



What you need to do is make sure that you are using a scatter (x-y) graph with lines connecting the points instead of a line graph. Note also that Excel, for some reason I cannot fathom, occasionally does not like plotting scatter graphs where there are empty cells in the data range and actually plots a category graph even though the chart format is set to scatter.

Answer 3

It sounds like you need to know how to figure out how to get the points. You need to make an xy chart. Some people call it a T chart. You need to pick three numbers for X, then substitute each of those into your equation. You multiply by three then add one. Whatever your answer is, that's your y value. In this case, I pick the numbers 0, 1, & 2. When you substitute 0 for X, you get y=1 because: y = 3x + 1 y = 3 (0) + 1 y = 0 + 1 y = 1 When you substitute 1 for x, you get y=4 because: y = 3x + 1 y = 3(1) + 1 y = 3 + 1 y = 4 When you substitute 2 for x, you get y=7 because: y = 3x + 1 y = 3(2) + 1 y = 6 + 1 y = 7 So your xy chart should look like this: X, Y 0, 1 1, 4 2, 7 So the points you should graph is (0,1), (1,4), & (1,4). Hint: It should be a straight line. I don't know where you got (0,4), that point should not be on the graph.