33. The accompanying table shows wind speed and the corresponding wind chill factor when the air temperature is 10 F

 Wind Speed (mi/h) Wind Chill Factor (F) 4 3 5 1 12 -5 16 -7 22 -10 31 -12

Write the logarithmic regression for this set of data, rounding coefficients to the nearest ten thousandth.
Using the equation, find the wind chill factor, to the nearest degree, when the wind speed is 50 miles per hour.
Based on your equation, if the wind chill factor is 0, what is the wind speed to the nearest mile per hour?

First, let’s get a science/physics/meteorology guy here. Does the context make sense?

But here’s the bad news: Logarithmic regression… calculator-trained kids can plug into the calculator (maybe). But e, the base of the natural logarithms, is not part of the curriculum associated with this exam. Talk about unfair!

Although logarithmic regression is in the curriculum, ln and e are not.  Based on the regression options of the TI-83/84 it makes logarithmic regression questions impossible to answer without developing base e or the natural logarithm.

A student is not able to get full credit on this 6 point question unless he or she has a full understanding of ln and e.

January 28, 2009 am31 7:55 am 7:55 am

How did you get this question, photographic memory?

January 28, 2009 am31 8:05 am 8:05 am

Just did the problem. 16 degrees and 6 mph. This is only after being clarified of what LN and e is. On the exam, I had no idea what ln really meant and how it relates to e.

January 28, 2009 am31 8:32 am 8:32 am

I ended up stressing out about it for half an hour, and finally giving up and doing a linear regression equation. A shame, because I’m fairly certain I did really well on the rest of the exam.

January 28, 2009 am31 8:41 am 8:41 am

Doing linear regression was the smartest thing you could do. It shows that you know what regression means. I did not do linear regression, I wrote how there is no possible equation. My Math Teacher said linear regression would get you 2 points, doing what I did would get you 0.

5. January 28, 2009 pm31 8:45 pm 8:45 pm

Since the calculator only does a natural log regression, does that mean when you teach logarithmic regression you do it by hand?

Yet the test was expecting the calculator to be used? Forget knowing about ln and e, how were students supposed to know what buttons to press?

6. January 28, 2009 pm31 8:51 pm 8:51 pm

Jason,

there is no answer to your question. The topics are outside of the curriculum.

Some NY State students, trained TI users, might flounder around with the buttons until they hit something. The domain errors might alert them to keep poking. And the cleverest might plot the data and get a rough idea of where the answer should be.

Some NY State students might be in a class where the teacher taught extra topics.

And some NY State students (I’m thinking of a paper I just graded) needed to retake Math B, but had moved on to precalculus, where natural logarithms were part of the course, and so were able to complete the question based on knowledge acquired at a subsequent level.

January 28, 2009 pm31 10:02 pm 10:02 pm

well i did every thing write, for this question.
I figured out that the wind speed is 6 because as you can see
4–3
5–1
12-(-5)
so if the temp is 0 the it has to be the number write after 5 which is 6, and thats how i found it out, yes its not really math, but i guess that my guess saved me.

8. January 29, 2009 am31 7:04 am 7:04 am

I’m not a NY teacher so I don’t have the grading rubric nor do I have the insight of those in the midst of this …

You can use a graphing calculator and logarithmic regression is part of the course – so the kids would know what lnreg means and how to enter the numbers into the lists.
Turn on plot 1, get the window.
LnReg Y1
trace x=50 and get the first answer; 2nd calc, zero to find the second.

Is there a “show your work by hand” requirement that I’m missing? This seems too “No-think-monkey push buttons” kind of a problem, no real understanding needed.

And no, the whole problem is idiotic. Not as bad as the Candy Store and the Olympic diver whose acceleration was upward when y>0 and whose path through the air had the wrong curvature, but still pretty lame.

9. January 29, 2009 am31 7:11 am 7:11 am

Curmdugeon,

log regression’s not in the curriculum (to my knowledge). No natural logs, no e, so the kids really were at a loss in many places.

10. January 29, 2009 am31 7:20 am 7:20 am

Ah, now it all makes sense. That is ridiculous.

I can’t wait to see the curve that will need to be applied to this one to pass enough people.

11. January 29, 2009 am31 7:35 am 7:35 am

This one won’t effect the curve. It was the next to last question, one of the hardest, and mostly will knock back the kids who were studying for 90s and 100s.

It’s an 88 point exam, and the curve is available here: http://www.emsc.nysed.gov/osa/concht/jan09/mathbcc-109.html

The question was a 6 pointer. Students could have easily stumbled into partial credit – but the state tried to limit it to 2 points without the log regression.

January 30, 2009 am31 2:45 am 2:45 am

I got 5 out of 6 points for that question

13. January 30, 2009 am31 5:26 am 5:26 am

January 30, 2009 am31 9:31 am 9:31 am

So does anyone know if they are scrapping this question (giving us the points for it) or is there no hop? Ugg I would like to see my grade rise a few points but I guess I am happy with what I got. =/