Chart Question?

Question

"The chart gives the average number of students per computer in public schools in America. Assuming a linear relationship, which is the best estimate for the number of students per computer during 1989-98?"

Year/Students per computer:

1990-91/20.0
1991-92/18.0
1992-93/16.0
1993-94/14.0
1994-95/10.5
1995-96/10.0
1996-97/7.8
1997-98/6.1

A) 5.4
B) 10.8
C) 20.2
D) 21.9"

I don't know how to get the answer. I've tried averaging the numbers, and also putting them into a TI-83+, going to STAT, insert the information, and find the LinReg (y=ax+b). What do I do? Please show how you got it so I understand it, thanks.

Answer 1

You're almost there!

1. Once you calculate LinReg, go to "y=".
2. Put your cursor in Y1 and click VARS.
3. Go to #5 Statistics.
4. Scroll over on the right to EQ.
5. Click #1 RegEQ.
6. Now your equation should be entered. Graph it and then go to the table to figure it out!

I don't have my calculator with me right now or I would tell the answer, but that's how you do it anyways! Hope I helped!

Answer 2

Never mind the answer: what is the question? The number of students per computer during *1989-98* doesn't make much sense (except as the average of the data over time, which needs no analysis at all). What was probably meant is one of the years outside the period for which data are available: either the year 1989-90 or 1998-99, or both. In either case, regress students/computer (y) on time (x), and apply the fitted relationship y = ax+b to the year in question.

But even w/o any calculation, there is very nearly a steady decrease of 2 per year. So for year 1989-90 the ans must surely be D (21.9), and for 1998-99 it must be A (5.4).

Answer 3

Since the number of computers per person is decreasing, the answer should be less than 6.1, the number in the latest year. Thus the answer should be "D", 5.4.

But if you have to show your work, try this:

Set up the data in a table and assign a number, like 0, to the first year. Then the data is:

x, y
0, 20.0
1, 18.0
2, 16.0
all the way up to
7, 6.1

Now what you want is an estimate for year 8.

So plug the above table into the linear regression thing in your calculator. It should give you the equation of a best-fit line, probably in slope-intercept form. Plug in x=8 into the regression equation and that will give you the y you need.

Or, after plugging in the data your TI-83 might be able to predict y for x=8. Hope this helps. Have fun with it!

Answer 4

The count steadily decreases and most recently by about 2 units per year. (The linear relationship implies a continuing trend with time as opposed to a polynomial equation where the function may change from a negative slope to positive.) With the last value of 6.1, I would expect a lower value. Only one solution in the multiple choices offered fits. All other solution listed are at least 4 units higher.

This really is a word-problem and less a problem that needs a TI-83 or other programmable calculator. Be sure to read a problem carefully before doing alot of unneccesary grunt work. Though it gives a table of numbers hinting at doing trend analysis, the negative trend is clear and contining trend is implied with the words "linear relatioship" in the question.

Answer 5

Nostradamus--- Astrologer and physician... Some of his prophecies appeared to be fulfilled and his fame became so widespread...Some believed that his prophecies are prefigured historical events that have occured during his time. Others having no apparent meaning, are said to foretell events that have not yet occurred... Harry Houdini--- Conjuror with his sensational escape...Another fellow with extraordinary (supernatural ability), earned his international reputation for his treatrical tricks, and daring feats of extrication from shackles,ropes and hadcuffs and from various locked containers... Two very interesting fellow with different supernatural talents, it makes me wonder what's the differences between their natal chart...

Answer 6

Brad They are Talking about you...!!
http://www.osoq.com/funstuff/extra/extra03.asp?strName=Brad

Answer 7

d because you can count faster