How do I chart two normal distribution curves in the one graph

If you right click on the graph and click on edit data or source data, you should be able to graph another set of data, depending on if you have office or vista, it may be under something different but will be very similar

Posted on Mar 18, 2008

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Ray is a bit off track, there are indeed a few mathematicians around Fixya.

Here you are dealing with the standard error of a proportion. The proportion of students of interest in the sample is 540/970 = 0.5567. This is usually denoted by p.

Now you want the standard error of this proportion, s. It is

SQRT ( p (1-p) / N ) where N is sample size. Note the error is smaller for big samples. Here s = 0.0160.

Now we turn to the Normal Distribution. We want the Z-statistic which corresponds to a confidence level of 92%, or 0.92. Z is the number of Standard Deviations on the Normal Curve which takes in 92% of the area under the curve. You can look this up in any table of the Normal Distribution, or with an online calculator

http://onlinestatbook.com/2/calculators/normal.html

This gives Z = 1.751. So the true result is somewhere in p ± (1.751 * 0.0160)

or 0.5567 ± 0.0279. The margin of error is 0.0279.

Now I don't know here if your tutor wants you to use a Continuity Correction, which is sometimes applied because we are approximating the Normal Distribution here. If so this is

0.5 / N = 0.5 / 970 = 0.0005.

This small amount is added to the Margin of Error, to make 0.0284.

A good reference for you to use is

http://onlinestatbook.com/2/estimation/proportion_ci.html

http://onlinestatbook.com/2/index.html

Here you are dealing with the standard error of a proportion. The proportion of students of interest in the sample is 540/970 = 0.5567. This is usually denoted by p.

Now you want the standard error of this proportion, s. It is

SQRT ( p (1-p) / N ) where N is sample size. Note the error is smaller for big samples. Here s = 0.0160.

Now we turn to the Normal Distribution. We want the Z-statistic which corresponds to a confidence level of 92%, or 0.92. Z is the number of Standard Deviations on the Normal Curve which takes in 92% of the area under the curve. You can look this up in any table of the Normal Distribution, or with an online calculator

http://onlinestatbook.com/2/calculators/normal.html

This gives Z = 1.751. So the true result is somewhere in p ± (1.751 * 0.0160)

or 0.5567 ± 0.0279. The margin of error is 0.0279.

Now I don't know here if your tutor wants you to use a Continuity Correction, which is sometimes applied because we are approximating the Normal Distribution here. If so this is

0.5 / N = 0.5 / 970 = 0.0005.

This small amount is added to the Margin of Error, to make 0.0284.

A good reference for you to use is

http://onlinestatbook.com/2/estimation/proportion_ci.html

http://onlinestatbook.com/2/index.html

May 12, 2015 •
Institute of Mathematics and Statistics...

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Here you are trying to find the intersection point between two curves. Since you could have drawn more than 2 curves, the calculator gives you the opportunity to choose the first curve using the arrow Up/ arrow down to select.

Once the curves are chosen, the calculator wants to know where (in the world is Carmen Sandiego) is the intersection point. And no it is not asking you to give the position, just what are the leftmost (1st guess) and rightmost (2nd guess) limits of the interval where the intersection point is. You use the left arrow to go a bit to the left of the intersection point (which you see on the graph) and press ENTER. Then you do the same for the 2nd guess.

Once the curves are chosen, the calculator wants to know where (in the world is Carmen Sandiego) is the intersection point. And no it is not asking you to give the position, just what are the leftmost (1st guess) and rightmost (2nd guess) limits of the interval where the intersection point is. You use the left arrow to go a bit to the left of the intersection point (which you see on the graph) and press ENTER. Then you do the same for the 2nd guess.

Dec 03, 2013 •
Texas Instruments TI-83 Plus Calculator

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You may be making a confusion between intercepts and intersections. Intercepts are crossing of the axes. Intersections are between two curves: You need to have two curves graphed. You choose the first curve by selecting it (Up or Down Key), and then the second one.

Oct 29, 2017 •
Texas Instruments TI-84 Plus Calculator

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Press Y=

On the Y1 line enter the expression LOG(X+2)+LOG(X+3) by pressing

LOG ALPHA [X] ) + LOG ALPHA [X] + 3 )

On the Y2 line enter the expression 7-X by pressing

7 - ALPHA [X]

Press GRAPH to see the graph. To see where they intersect, press 2ND [CALC] 5. See "First curve?" in the lower left. Use up/down-arrow to select one of the two curves and press ENTER. See "Second curve?" in the lower left. Use up/down-arrow to select the other curve and press ENTER. See "Guess?" in the lower left. Press ENTER. The calculator will show the coordinates of the intersection.

On the Y1 line enter the expression LOG(X+2)+LOG(X+3) by pressing

LOG ALPHA [X] ) + LOG ALPHA [X] + 3 )

On the Y2 line enter the expression 7-X by pressing

7 - ALPHA [X]

Press GRAPH to see the graph. To see where they intersect, press 2ND [CALC] 5. See "First curve?" in the lower left. Use up/down-arrow to select one of the two curves and press ENTER. See "Second curve?" in the lower left. Use up/down-arrow to select the other curve and press ENTER. See "Guess?" in the lower left. Press ENTER. The calculator will show the coordinates of the intersection.

Sep 19, 2012 •
Texas Instruments TI-84 Plus Calculator

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Curves drawn with the help of a graphing calculator are no mere sketches, they are a lot more accurate than a human hand will be able to draw.

Unfortunately for you, the calculator you are using is no graphing calculator and thus cannot draw. However, it is able to generate a table of values which you might use to sketch curve on a sheet of graph paper.

Unfortunately for you, the calculator you are using is no graphing calculator and thus cannot draw. However, it is able to generate a table of values which you might use to sketch curve on a sheet of graph paper.

Feb 14, 2012 •
Casio FX83ES Scientific Calculator

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You are not being very clear about the problem. You want a curved line and the calculator gives you a straight line? If that is the case, then it is like the Earth. If you look at it too closely you will not notice that it is round, while if you see it from space it is round. The solution is to Zoom out. Increase the range Xmax-Xmin, and Ymax-Ymin. You will see more of the graph and the curve will show.

Sep 09, 2011 •
Texas Instruments TI-84 Plus Calculator

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Ok, try these two things and you should be just fine.

1.) Check your range for your graph. It is possible that the range you are using isnt large enough to show the curve. Also try using Z-fit vs Z-st. These are options that your calculator will give you once the equation is graphed.

2.) Place a parenthesis around the 2x, make sure that you and the calculator are both using the same order of operations. This move mill ensure that the calculator will multiply the variable, x, by two and then do the exponential.

This should do it!

Happy Graphing!

1.) Check your range for your graph. It is possible that the range you are using isnt large enough to show the curve. Also try using Z-fit vs Z-st. These are options that your calculator will give you once the equation is graphed.

2.) Place a parenthesis around the 2x, make sure that you and the calculator are both using the same order of operations. This move mill ensure that the calculator will multiply the variable, x, by two and then do the exponential.

This should do it!

Happy Graphing!

Jul 25, 2010 •
Texas Instruments TI-84 Plus Calculator

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I believe I already showed you with a profusion of details how to graph functions on the calculator. It would very kind of you to refer to the post that answered your question, so as not to make us answer it all over again. Much appreciated.

Read the following to use the intersection function.

Here are some screen captures

Read the following to use the intersection function.

- You draw two or more graphs.
- After the graphs are displayed, press [2nd][TRACE] to access the (CALC)ulate menu.
- Select [5:Interesct]
- You will be prompted for a first curve: the equation of the curve will be displayed at the top left corner of the screen. If it is one the intersecting curves, press [ENTER]
- You will be prompted for the second curve. (You can move from one curve to another by pressing the UpArrow or DownArrow).
- After two curves are selected, you will be prompted for a guess for the X-value of an intersection point: you can use the keypad to enter a guess or use the left or right arrow to move the cursor towards a point of your choosing (if there are more than one point).
- After a short while the calculator gives you a solution.
- If it fails, you must make a better guess.

Here are some screen captures

May 12, 2010 •
Texas Instruments TI-83 Plus Calculator

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- You draw two or more graphs.
- After the graphs are displayed, press [2nd][TRACE] to access the (CALC)ulate menu.
- Select [5:Interesct]
- You will be prompted for a first curve: the equation of the curve will be displayed at the top left corner of the screen. If it is one the intersecting curves, press [ENTER]
- You will be prompted for the second curve. (You can move from one curve to another by pressing the UpArrow or DownArrow).
- After two curves are selected, you will be prompted for a guess for the X-value of an intersection point: you can use the keypad to enter a guess or use the left or right arrow to move the cursor towards a point of your choosing (if there are more than one point).
- After a short while the calculator gives you a solution.
- If it fails, you must make a better guess.

Apr 19, 2010 •
Texas Instruments TI-84 Plus Calculator

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Graph the function then use the trace function to locate the point(s) where two curves intersect. In your case one of the curves is the X-AXIS.

See the screen capture to learn how to use the trace functionality.

See the screen capture to learn how to use the trace functionality.

Feb 05, 2010 •
Casio FX-7400G Plus Calculator

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