Homework Help needed in AP Biology Please

The teen is working The Chi Square test often used in science to test if data you observe from an experiment is the same as the data that you would predict from the experiment.

Anyone know about this? She needs some help and has the data already on a spreadsheet but even with the teacher explaining it to her early this morning writing out a sample she is struggling. Seems like her phone is ringing off the hook with others in the same class who cannot figure this one out. Phone is turned off and we are looking for help, not the answer!

Thanks,
Sherry

P.S. I'm looking at this link for help: http://www2.lv.psu.edu/jxm57/irp/chisquar.html

Not sure if it is the right on.

 

I bet Wayne can help. I think this is really what he is an expert in (science stuff). Holler if she needs help with AP English.

 

Thanks for letting me know about the AP English. Seems she is doing okay but the Vocabulary Exam has 147 words and definitions to remember by Friday.

Will give you a holler, if needed,
Sherry

 

This is kind of difficult to explain like this but maybe I can help.

What is her number of options for results?

 

As in your example link, you should have a spreadsheet set up as example B1 with a column for each of your options. In the case of the example there are only two options thus two columns.

 

Told ya! :cheers:

 

Wayne,

I am scanning in the instructions, her excel spreadsheets and the numbers her teacher came up with today. His numbers do not add up to me to make the equations correct nor do they for her. Will attach the scanned stuff in a minute.

Thank you so very much,
Sherry

 

For each of the options you will list the observed data, expected data, the difference in numerical terms, and the square of the difference for each column. You will then divide the square of the difference by the expected data number for each column and add them together to get your'2' value.

Once you have that number you will chech the table B2 for the number of options less one (degree of freedom) row. In the case of 2 options you use the 1 degree of freedom row. You will find the probability numbers on either side of your '2' value. If the higher number is greater than 0.05 the variation is acceptable for your hypothesis, but if it is 0.05 or lower you have other variables in play and the hypothesis is not valid.

 

Not a problem, it is kind of hard to work in the blind so to speak.

 

The last scan is the one the teacher wrote for her but she nor I can come up with his numbers. We find his numbers to not add up to what is on the spreadsheet. Not sure if we are doing it correctly and she is having a hard time with this Lab because of Chi, which neither of seem to understand.

Thank you so very much for taking the time to help. She does not have to complete this Lab until the end of the week but she was trying to stay ahead of the game, so please take your time to review and see if you can get back us tomorrow or the next day. We do understand it is late tonight and you are a busy person.

Thanks again, Wayne,
Sherry

 

The best hypothesis would most likely be the equal distribution of the different colors in the candy.

Outside of that it depends on the candy itself.

Each color would be a column on the spreadsheet.

Listed would be the expected (total number of candy pieces/number of colors)

The observed (total number of each color counted)

The difference of each observed from the expected.

The square of the difference for each.

The square divided by the expected for each column.

You would then add all of the squares divided by the expected values to get one number.

Go to the table listing the probabilities and pick the row with the number of colors-1 (degrees) .

Look across the table until you find the column with a number above and below the value you determiend from adding all of the squares divided by the expected values.

If the column is greater than 0.05 the hypothesis is valid. If not it is invalid and another hypothesis must be determined for the distribution.

Adjust the expected value based on the hypothesis until you get a valid hypothesis based on the table results being greater than 0.05

 

If she uses her numbers that she put together on the spreadsheet and takes Cross # 2B. Under F3 she would add the 110 vg, 144 vg, 471 and 456 for a total of 1,202. Same F3 and the number 625 and 583 vg. On the Johnston County Schools scan her teacher states that F3 with the 625 vg and 583 vg equal 1208. It actually adds up 1202. What are we missing? I guess if she could understand that one she would probably figure out the rest.

Thanks,
Sherry

 

OK. I see her page now, sorry.

Some of the math seems to be slightly off.

Red -0.4*-0.4=0.16 0.16/8.4= 0.02 (the 0 to the left of the decimal place is not included as a significant digit)

Other than a slight difference in the math everything else looks good to me.


Since the hypothesis was accepted I do not know if you needed to do anything for 3.

 

I think that problem was supposed to be three variables with the 1208 being the third variable. The second listing seems to show no difference from the observed and expected for that group and only a difference of 5 each for the other two.

F1 = one variable always correct.
F2 = two variables
F3= three variables

 

What are you talking about when you speak of colors? The data on the sheet with the colors (blue green, brown yellow and red). My teacher has us do an M & M lab where we took a cup full of m& m's and separated them into groups by colors. we then had to place by color what exactly we saw. I had to put those numbers in the observed column.
Lets talk about the blue m& m's for this exmple. My teach gave me the standard data from a site that makes the candy and it was 23% blue in any one given bag of m & ms. i took my 12 that i had in my cup full and multiplied it bt . 23 and that is how i got my expected.
Somehow all of this data that i used is suppose to be transferred into my fly lab. If it does not say the + after a number means that those flies from each cross were wild. The vg means that the flies were vestigial, the bw means that the flies had brown eyes, se means that the flies had sepia eyes, and the pr means purple eyes and the c means that the flies had curved wings.
-sherry's teen

 

F1 = 0
F2 = 39 difference for both
F3 = 0 for one and 5 difference for the other two

At least that is how it seems to me given what was written in the second grouping. Even then there are missing pieces that must be assumed (the 39 difference for the first value for example)

 

mr.wayne,
what i really need help with is the two excel spreadsheets, and the sheet that shows lab #7 genetics. Mom scanned count and record sheet and it should not have been. disregard.

thanks,
the teen

 

I was basing that on the first posting of the sheet I saw, which did not have your percentages. You should probably just ignore that because you have the right ideas in your worksheet.

 

OK, I will have to look at those more closely in the morning, but I will try to do it first thing for you.