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Posted on Jan 02, 2017

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SOURCE: Linear regression

I already answered a Q like this - you can't do 2 variable statistics on the TI-30XA, it only does one variable statistic.

To do 2 variable stat like linear regression, you need the TI-36X or TI-30X IIS, or comparable HP, casio etc

Posted on Jan 01, 2009

SOURCE: Solving matrix

Go to your matrix button and enter a "3x4" matrix.

Then enter it as follows:

-3 4 5 7

4 3 2 9

-5 5 3 -10

Then exit out and go to "2nd->matrix->math->rref(". Then press enter.

Your screen should look like this:

rref(

Then go to matrix and select your 3x4 matrix, press enter and close it with a parathesis. Your screen should look like this:

rref([A])

Press enter and the screen should say this:

1 0 0 2

0 1 0 -3

0 0 1 5

So,

x=3

y=-3

z=5

Hope this cleared up the confusion!

SJ_Sharks

Posted on Mar 14, 2009

SOURCE: 4x+3y=6 how do you solve for y

Hello,

I am not lecturing you but I would rather you understand how to do the manipulations involved in isolating a variable.

You want to isolate y, Ok

Start stripping it of all that is not y.

3y + 4x =6. (Addition is commutative, I can change the order of addition)

The term with y is** added **to 4x. If I want the term in y alone on one side I perform the** inverse operation of addition**, a **substraction**. I subtract 4x from both sides.

3y+4x-4x=6-4x. But 4x-4x=0, and we are left with

**3y= - 4x+6**

This operation is sometimes summarized as make one term change side while changing its sign

It would do no harm to put the right side of the foregoing equation in parentheses. I do that to avoid errors)

3y= (-4x+6).

Now y is **multiplied** by the number 3. To isolate y I have to perform the **inverse operation** of the multiplication, namely the division by 3

3y/3 =(-4x+6)/3. The left hand side is just y**y= (-4x+6)/3.**

While result is correct, I can also open the parentheses

y= -4x/3 +6/3**y= -(4/3)*x +2.**

Hope it helps.

Posted on Oct 30, 2009

SOURCE: You are given the following data.

OK, you convinced me to do your homework for you.

Before doing statistics, you have to prepare the calculator by clearing old data that may generate errors.

A. To clear old data

- Press [2nd][+] (MEM) to open the memory management screen.
- Press [4:ClrAllLists]
- The command echoes on main screen, press [ENTER] to run it.
- Calculator displays Done.

- Press [STAT][5:SetUpEditor] [ENTER] ; calculator displays Done.

To obtain the correlation coefficient in a statistical analysis on the TI8xPlus family of calculators you must activate the DiagnosticsOn option. To access the command

- You press [2nd] [0] (CATALOG)
- While the list of commands is displayed, press [X^-1] (D)
- Cursor jumps to first command that starts with D, dayOfWk(
- Press the DownArrow 9 times to reach DiagnosticsOn
- Select it and press [ENTER]
- Command echoes on main calculator screen with blinking cursor
- Press [ENTER] to set the option
- Calculator displays Done.

D. Enter the data

Press [STAT][1:Edit]

Type in the X values in L1 and the Y values in L2 (see picture 1)

To obtain the statistical results

- After you finish entering the data, press [2nd][Quit] to exit StatEditor.
- Press [STAT] and highlight Menu (CALC)
- In the list select [2:2-Var Stats]
- Command echoes on main screen.
- Press [ENTER] to calculate the stats

Notice the down arrow next to n=7. That means the results screen has more values. Press the down arrow to display.

You notice that the n=7 line now has an arrow pointing Up. Notice the Down Arrow on the bottom line (more data is coming). Here is the rest of the statistical results.

There is no arrow at the bottom of the picture. End of statistical results.

The screen captures with 2-Var Stats summarize all the satistics. Some of the values your are looking for are among the result. NOW it is you mission to identify what you need (I chewed all the work for you).

However there is no correlation coefficient, no line of best fit, etc. To obtain that you have to perform a regression analysis.

Perform a Regression analysis

To perform a regression analysis, you must try several regression models and then find the one that mimicks the raw data best. In this particular case, you have already decided to do a linear regression, and that is good for me. I do not have the time to take you through all of them. A linear regression it will be.

- Press [STAT] , highlight [CALC]
- In the list of regression models select [4:LinReg (ax+b)
- The command LinReg(ax+b) echoes on main calculator screen.
- If you press [ENTER] you will get you equation but you will not be able to draw the curve on top of your data to verify the goodness (no it is not a swear word) of the fit. So you must save the equation as a function in Y1 variable.
- While LinReg(ax+b) command is still in command line, press the [VARS] key.
- Highlight the [Y-VARS] menu and select [1:Function], then press [ENTER].
- In the Y function variable list select [1:Y1]
- At the command line, you have LinReg(ax+b) Y1.
- Press [ENTER] to save the equation of best fit in Y1.

The slope is a and the y-intercept is b. You also have r and its square. You need to read your theory to know which of the two correlation coefficients you have been asked to obtain.

Since you saved the equation in the Y1 function you can draw it. You just have to press GRAPH and it will be drawn. But that will not tell how good the fit is, until you see the function drawn on top of the raw data.

Drawing the scatter plot and the raw data on the same screen.

Regardless of the curve of best fit, you can draw a scatter plot as follows.

- Press [2nd][Y=] (STATPLOT)
- Select [1:Plot1...Off] to open plot1 configuration screen
- Use arrow to highlight On
- Use the down arrow to move cursor to the line Type.
- Select the first icon for a scatter plot. NOTE: To navigate the 6 statistical stat plots on the line Type, use the right or left arrow (to backtrack), but not the Up or down arrows.

Here plot1 is active (ON), it is scatter plot (first icon) the Xlist is L1 by default but you can change it to some other list. Notice the highlighted A cursor on XLIST line. It means that the [ALPHA] keyboard is active.

On the line Mark you can choose the appearnce of the raw data point.

And here is your two graphs: the raw data scatter plot and the line of best fit on the same screen

Now, it is up to you to accept this model or to try another model.

N

Posted on Jan 21, 2010

SOURCE: how do i put and x or y or m into and equation

Rename your variable (unknown) X, because the calculator takes X as the default unknown. It will ask you "Solve for X?"

the 7, the second minus sign, 3 and 11 use the relevant keys.

For the first minus sign use the negation key or change sign (-)

For the variable X, examine the calculator keys on the row where the parentheses are. To the right corner of the key area there is a symbol in the same color as the ALPHA key. I believe the X is under the right parenthesis, or thereby.

To enter the X variable you press [ALPHA][ )]. To enter the = sign, you press [ALPHA] [CALC].

To execute the solve command, press [SHIFT] [CALC] and you will be prompted " Solve for X?"

Posted on May 07, 2010

To graph this equation, we see that it is in the slope/intercept form of y=mx + b, where m is the slope and b is the y-intercept.

d(t)= -2t+18

Start with the y-intercept of 18 (0,18)

From this point, we can start graphing the line by using the slope of -2. Since the slope is negative, it goes up to the left. So we go one to the left, and up two.

Good luck.

Paul

d(t)= -2t+18

Start with the y-intercept of 18 (0,18)

From this point, we can start graphing the line by using the slope of -2. Since the slope is negative, it goes up to the left. So we go one to the left, and up two.

Good luck.

Paul

Nov 30, 2016 | Office Equipment & Supplies

The easiest way to solve and graph and equation is to put the equation into the slope intercept form y = mx + b, where m is the slope and b in the y-intercept.

To do this, we subtract 4x from both sides and get y = -4x + 0.

From this we know m = -4 (slope) and the y-intercept is 0.

I always start with the y-intercept and put a point there. Thus, we have a point at (0,0). Using this as a starting point, we now use the slope of -4 to get future points. Since it is negative, we go one unit to the left and up four units. So we have the point (-1,4). Using a ruler, we connect these points and continue on both sides to produce the line.

There is also a great free online program/app called Desmos that you can use to check your work. Type in the equation of the line and it will graph it for you.

Good luck,

Paul

To do this, we subtract 4x from both sides and get y = -4x + 0.

From this we know m = -4 (slope) and the y-intercept is 0.

I always start with the y-intercept and put a point there. Thus, we have a point at (0,0). Using this as a starting point, we now use the slope of -4 to get future points. Since it is negative, we go one unit to the left and up four units. So we have the point (-1,4). Using a ruler, we connect these points and continue on both sides to produce the line.

There is also a great free online program/app called Desmos that you can use to check your work. Type in the equation of the line and it will graph it for you.

Good luck,

Paul

Oct 27, 2016 | Office Equipment & Supplies

The easiest way to solve and graph and equation is to put the equation into the slope intercept form y = mx + b, where m is the slope and b in the y-intercept.

To do this, we subtract 4x from both sides and get y = -4x + 0.

From this we know m = -4 (slope) and the y-intercept is 0.

I always start with the y-intercept and put a point there. Thus, we have a point at (0,0). Using this as a starting point, we now use the slope of -4 to get future points. Since it is negative, we go one unit to the left and up four units. So we have the point (-1,4). Using a ruler, we connect these points and continue on both sides to produce the line.

There is also a great free online program/app called Desmos that you can use to check your work. Type in the equation of the line and it will graph it for you.

Good luck,

Paul

To do this, we subtract 4x from both sides and get y = -4x + 0.

From this we know m = -4 (slope) and the y-intercept is 0.

I always start with the y-intercept and put a point there. Thus, we have a point at (0,0). Using this as a starting point, we now use the slope of -4 to get future points. Since it is negative, we go one unit to the left and up four units. So we have the point (-1,4). Using a ruler, we connect these points and continue on both sides to produce the line.

There is also a great free online program/app called Desmos that you can use to check your work. Type in the equation of the line and it will graph it for you.

Good luck,

Paul

Oct 27, 2016 | Office Equipment & Supplies

Let's break this down into a few parts first.

Slope intercept form is otherwise known as y = mx + b, where m is the slope and b is the y-intercept.

Parallel means that the two lines will never meet. They are parallel to each other. In math terms, their slopes are the same, so the m values must be the same.

Starting with y = -5x + 1, putting into slope intercept form, y = mx + b, m = -5 and b=1.

Since it is parallel, it must have the same slope and the m values are the same.

So, y = -5x + b, but we don't know what the value of b is. To determine this, we know the point (-4,-6) is on the line that we are trying to find, so we can substitute it into the equation and calculate b to make it work.

Every time we see an x we put in -4 and every time we see a y, we put in -6.

-6 = -5(-4) + b

-6 = 20 + b

subtract 20 from both sides

-6 - 20 = 20 + b - 20

-26 = b

Now substitute this into the equation.

y = -5x + -26

Putting it into correct form, we get y = -5x - 26.

Let's check it to see if it is correct.

It has a slope of -5, so it is parallel to y=-5x + 1

Is the point (-4,-6) on the line? Let's substitute it in to see if it is on the line.

Again, everywhere we see an x, we put in -4 and everywhere we see a y we put in -6.

-6 = -5(-4) - 26

-6 = 20 - 26

-6 = -6

Sorry for the very long explanation, but after you do a few of them, you will be able to knock them off in minutes.

Good luck,

Paul

Slope intercept form is otherwise known as y = mx + b, where m is the slope and b is the y-intercept.

Parallel means that the two lines will never meet. They are parallel to each other. In math terms, their slopes are the same, so the m values must be the same.

Starting with y = -5x + 1, putting into slope intercept form, y = mx + b, m = -5 and b=1.

Since it is parallel, it must have the same slope and the m values are the same.

So, y = -5x + b, but we don't know what the value of b is. To determine this, we know the point (-4,-6) is on the line that we are trying to find, so we can substitute it into the equation and calculate b to make it work.

Every time we see an x we put in -4 and every time we see a y, we put in -6.

-6 = -5(-4) + b

-6 = 20 + b

subtract 20 from both sides

-6 - 20 = 20 + b - 20

-26 = b

Now substitute this into the equation.

y = -5x + -26

Putting it into correct form, we get y = -5x - 26.

Let's check it to see if it is correct.

It has a slope of -5, so it is parallel to y=-5x + 1

Is the point (-4,-6) on the line? Let's substitute it in to see if it is on the line.

Again, everywhere we see an x, we put in -4 and everywhere we see a y we put in -6.

-6 = -5(-4) - 26

-6 = 20 - 26

-6 = -6

Sorry for the very long explanation, but after you do a few of them, you will be able to knock them off in minutes.

Good luck,

Paul

Apr 03, 2016 | Office Equipment & Supplies

Let's break this down into a few parts first.

Slope intercept form is otherwise known as y = mx + b, where m is the slope and b is the y-intercept.

Perpendicular means that the two lines will intersect each other at a 90 degree angle. In math terms, their slopes will be negative reciprocals of each other.

Starting with y + 4 = 1/4(x -7), putting into slope intercept form, y = mx + b, m = 1/4 and b=-7/4 -4.

Since it is perpendicular, it must have a slope that is a negative reciprocal. The slope of the original line is 1/4, so the multiplying it -1, we get -1/4, and taking the reciprocal, we get -4. So the slope of the perpendicular line is -4.

So, y = -4x + b, but we don't know what the value of b is. To determine this, we know the point (-4,7) is on the line that we are trying to find, so we can substitute it into the equation and calculate b to make it work.

Every time we see an x we put in -4 and every time we see a y, we put in 7.

y = -4x + b

7 = -4(-4) + b

7 = 16 + b

subtract 16 from both sides

7 - 16 = 16 + b - 16

-9 = b

Now substitute this into the equation.

y = -4x + -9

Putting it into correct form, we get y = -4x - 9.

Let's check it to see if it is correct.

It has a slope of -4, so it is perpendicular to y=1/4x - 5 3/4.

Is the point (-4,7) on the line? Let's substitute it in to see if it is on the line.

Again, everywhere we see an x, we put in -4 and everywhere we see a y we put in 7.

y= -4x - 9

7 = -4 (-4) - 9

7 = 16 - 9

7 = 7

Sorry for the very long explanation, I was being overly thorough, but after you do a few of them, you will be able to knock them off in minutes.

Good luck,

Paul

Slope intercept form is otherwise known as y = mx + b, where m is the slope and b is the y-intercept.

Perpendicular means that the two lines will intersect each other at a 90 degree angle. In math terms, their slopes will be negative reciprocals of each other.

Starting with y + 4 = 1/4(x -7), putting into slope intercept form, y = mx + b, m = 1/4 and b=-7/4 -4.

Since it is perpendicular, it must have a slope that is a negative reciprocal. The slope of the original line is 1/4, so the multiplying it -1, we get -1/4, and taking the reciprocal, we get -4. So the slope of the perpendicular line is -4.

So, y = -4x + b, but we don't know what the value of b is. To determine this, we know the point (-4,7) is on the line that we are trying to find, so we can substitute it into the equation and calculate b to make it work.

Every time we see an x we put in -4 and every time we see a y, we put in 7.

y = -4x + b

7 = -4(-4) + b

7 = 16 + b

subtract 16 from both sides

7 - 16 = 16 + b - 16

-9 = b

Now substitute this into the equation.

y = -4x + -9

Putting it into correct form, we get y = -4x - 9.

Let's check it to see if it is correct.

It has a slope of -4, so it is perpendicular to y=1/4x - 5 3/4.

Is the point (-4,7) on the line? Let's substitute it in to see if it is on the line.

Again, everywhere we see an x, we put in -4 and everywhere we see a y we put in 7.

y= -4x - 9

7 = -4 (-4) - 9

7 = 16 - 9

7 = 7

Sorry for the very long explanation, I was being overly thorough, but after you do a few of them, you will be able to knock them off in minutes.

Good luck,

Paul

Apr 03, 2016 | Office Equipment & Supplies

The "slope intercept form of the equation of a (the) line" is y=mx+b, where m is the slope of the line and b is the y-intercept.

We are given the slope of 1/2, so m= 1/2.

We can now write y=1/2 x + b.

Since the point (-2,-3) is on the line, we can substitute it in and solve for b. We put the -2 in for x and -3 in for y.

-3 = 1/2(-2) +b

-3 = -1 + b

-3 + 1 = -1 + b +1

-2 =b

Thus, the equation of the line is y= 1/2 x -2

To check if we did this correctly, plug in the point (-2, -3) to see if it works.

Left Side Right Side

-3 = 1/2 (-2) -2

= -1-2

= -3

We are given the slope of 1/2, so m= 1/2.

We can now write y=1/2 x + b.

Since the point (-2,-3) is on the line, we can substitute it in and solve for b. We put the -2 in for x and -3 in for y.

-3 = 1/2(-2) +b

-3 = -1 + b

-3 + 1 = -1 + b +1

-2 =b

Thus, the equation of the line is y= 1/2 x -2

To check if we did this correctly, plug in the point (-2, -3) to see if it works.

Left Side Right Side

-3 = 1/2 (-2) -2

= -1-2

= -3

Feb 24, 2015 | Office Equipment & Supplies

Assuming the 'standard form' is "slope-intercept", calculate the slope from the equation m = __y2-y1__ =__ 5 - 1__ = __ 4__ = -2

x2-x1 4 - 6 -2

The intercept can be found by substituting either of the two points into the equation y = mx + b

5 = (-2)4 + b

5 = (-8) + b

13 = b

(OR, using the other point, y = mx + b

1 = (-2)6 + b

1 = (-12) + b

13 = b )

Then expressing in general:

**y = (-2) x + 13**

x2-x1 4 - 6 -2

The intercept can be found by substituting either of the two points into the equation y = mx + b

5 = (-2)4 + b

5 = (-8) + b

13 = b

(OR, using the other point, y = mx + b

1 = (-2)6 + b

1 = (-12) + b

13 = b )

Then expressing in general:

Oct 10, 2014 | Computers & Internet

The equation of a straight line can be cast into several forms: functional form, general form, symmetrical form. The functional form is the one usually known as slope intercept form.

In the functional form, y=ax+b or sometimes y=mx+b, the factor of the x-variable (a or m as the case may be) is the slope of the straight line, and the value b, is the ordinate (y-value) of the point where the straight line cuts (intercepts) the y-axis.

Since you say nothing about the particulars of the line that interests you, there is not much more that anybody can help you with.

In the functional form, y=ax+b or sometimes y=mx+b, the factor of the x-variable (a or m as the case may be) is the slope of the straight line, and the value b, is the ordinate (y-value) of the point where the straight line cuts (intercepts) the y-axis.

Since you say nothing about the particulars of the line that interests you, there is not much more that anybody can help you with.

Mar 25, 2012 | SoftMath Algebrator - Algebra Homework...

To find the solution, first find the value of y for each equation.

Then substitue one equation into the other so that you only the x variable left.

Then just solve for x.

Once you have a value for x, then you can easily solve for y.

So for the first equation:

3y - 6x = -3

3y = 6x - 3

**y = 2x - 1**

Now for the second equation:

2y + 8x = 10

2y = -8x + 10

**y = -4x + 5**

Since both equations equal y, they also equal each other, therefore:

2x - 1 = -4x + 5

Now just solve for x:

2x + 4x = 5 + 1

6x = 6

**x=1**

Now substitute x=1 into either original equation:

y = 2x - 1

y = 2 (1) - 1

y = 2 - 1

**y = 1**

Therefore the solution is x=1 and y=1

Good luck, I hope that helps.

Joe.

Then substitue one equation into the other so that you only the x variable left.

Then just solve for x.

Once you have a value for x, then you can easily solve for y.

So for the first equation:

3y - 6x = -3

3y = 6x - 3

Now for the second equation:

2y + 8x = 10

2y = -8x + 10

2x - 1 = -4x + 5

Now just solve for x:

2x + 4x = 5 + 1

6x = 6

y = 2x - 1

y = 2 (1) - 1

y = 2 - 1

Good luck, I hope that helps.

Joe.

Nov 09, 2011 | Texas Instruments TI-84 Plus Silver...

use the slope-intercept form to graph y=2/3x+4

Mar 31, 2010 | Computers & Internet

Dec 13, 2017 | Office Equipment & Supplies

Dec 13, 2017 | Office Equipment & Supplies

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