Statistical Analysis

Today students in E period finished the chocolate statistics lab and we recapped the syllabus points for Statistics (see below and click the pictures to make them larger).  You also have these syllabus points on the back of the Topic 2.4 Syllabus

Mark your calendars because on January 18th, you will have a quiz on statistics.  Check out Mr. T's PowerPoint below for an excellent explanation of Stats.

Statistical Analysis

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Chocolate Statistics

Chocolate statistics

Initial observations

Look at your chocolates. Which do you think has the greater mass, a Smartie or an M&M? Or do you think they have the same mass?

Now touch your chocolates and ask yourself the same question.

Create a Hypothesis 1 (H₁) _{(alternative)} and a Null Hypothesis (H₀ )

Data Collection

How many Smarties/ M&Ms do you think you would need to measure the mass of to collect enough data to be sure of your answer?

Measure the mass of your Smarties. Now do the same for your M&Ms.

Record the data in an appropriate table. Don’t forget to include the units and the uncertainties of your equipment.

Data Processing

Calculate the arithmetic mean mass for your Smarties.

 Now do the same for your M&Ms.

Calculate the Standard Deviations.

Perform an unpaired t-test on your results.

Data Presentation

Draw a graph of your results. Include error bars.

Conclusion and Evaluation

Which hypothesis can you accept/reject and why?

What were the possible errors in your experiment?

Calculating Standard Deviation

The Standard deviation (SD, s or ) of the mean tells us how spread out the reading are ( the ‘spreadoutness’ of the data).

1. Calculate the mean

2. Measure the deviations

3. Square the deviations

4. Add the squared deviations

5. Divide by the number of samples minus 1

6. Square root the answer

Ask your math teacher to show you how to calculate the standard deviation on your calculator. Or…. Just use Excel :)

The unpaired t-test

Go to

http://www.graphpad.com/quickcalcs/ttest1.cfm

and enter your data.

Your analysis is due by the on Thursday.

Topic 1: Statistics

Statistics and using spreadsheets are an important aspect in an scientific field.

Today (or tomorrow for H period), students completed the following activity.

Excel can be used for many things: quickly finding the mean for a set of data, calculating standard deviation and even......... making a cartoon of Mike Tyson. Today students completed a worksheet on their computers where they needed to manipulate sets of data. Below is the worksheet with the hyperlinks.

Using Excel to Manipulate Data

A. Open the first file: 2003 American League Baseball Salaries

1. List three ways in which you could manipulate this data.

2. Sort the data so that each position is grouped together. Make sure that the salary of each player stays with the correct position. How many catchers are there?

Find the mean salary for each of the positions and fill in the information in the table below.

Catcher	1st Base	Outfielder	Shortstop	Pitcher	3rd base	2nd base

Which position has the highest mean salary?

B. Open the Price of Electricity file.

3. How many years have complete records for the price of electricity?

4. Create a scatter plot in Excel (or numbers) showing the average price in electricity for the years 1986-1995. Make sure to correctly label the x and y axis and write a title for the graph. Add your graph to this word document. Unsure how to make an xy scatter plot? Click through this PowerPoint if you are a Mac user.

5. In your own words, explain standard deviation in the space below. If you don’t know what standard deviation is, read about it here (it’s the first term on the list).

6. Go back to your Excel / Numbers file. Calculate the standard deviation for 1986-1995. To do this, click in the cell next to the annual average and type =STDEV(

Then highlight the data for each month in that specific year

Close the ) and press enter/return.

Highlight this cell and place the cursor on the edge of the cell so it changes from an arrow to a +

Drag the blue edge straight down the column, until you have reached 1995.

You now have the standard deviation for each year.

7. Add standard deviation bars to your graph. If you do not know how to do this, watch this video if you use a Mac or watch this video if you have the new version of Windows. You may only be able to add the error bars for three years at a time.

8. Turn your graph from an xy scatter plot into a bar graph. Again, make sure it is correctly labeled.

9. What does the green triangle in the left top corner of each standard deviation box signify?

10. Which year had the most consistent gas price?

11. Which year had the largest standard deviation? What does this tell you about the gas prices that year, compared to the other years?

12. On a scale of 1-10 (ten being impossible, one being super easy) how hard was this assignment? Please write the name of each person in the group and his/her response

13. Please complete the feedback table below. For each of the four tasks, please write if you already knew how do to this or what it is. Write yes if you knew it before or no if you didn’t not know it before class today.

Name	What standard deviation is	How to find standard deviation	How to add error bars to a graph	How to find the mean using Excel

Wrapping up Cell Membranes

Today we finished learning about cell membranes, specifically active transport, endo/excytosis and the role that vesicles play in transporting proteins throughout the cell.  Below are a list of links to the animations we watched in class.

Exocytosis (go to slide 12)
Endocytosis
Vesicles are used to transport proteins (the golgi video)
The Sodium-Potassium pump

Homework:  A typed, paper copy of your experimental design is due Monday or Tuesday, depending on when your class meets.   Since this should be pretty much done, you also have a DBQ due on Monday / Tuesday as well.  The DBQ is also on page 33 of your book.

Osmosis Design Practice

Yesterday and today students had the opportunity to 'play' in the lab using their experimental designs.  Here are some of the things they learned:

It's nearly impossible to transfer yogurt into dialysis tubing.

"Place half of the potato in water" is a completely unacceptable statement in a procedure.

Knowing what equipment is available will making writing a procedure much easier.

Measure in grams, not in "pinches" or "teaspoons."

After you've had a chance to 'play' it's OK and sometimes advisable to completely change your procedure.

Be Specific!
Be Specific!
Be Specific!

Tomorrow you will have class time to continue working on your designs.  The final design, following the guidelines you were given in class (at the back of the packet and have been emailed) will be due on Monday or Tuesday, depending on when your class meets.  You MUST have a printed copy of this assignment.

Experimental Design

Today we talked about experimental design and students were given the pages from the Syllabus that specifically address what assistance they can and can not receive from me.

After reviewing independent and dependent variables, we learned about the 5 x 5 model of experimental design.  Below is a sample 5 x 5 design for an experiment examining the effect of salt concentrations on the growth of bean seeds. 

On Monday or Tuesday of next week you will be carrying out this experiment. You will also have class on Wednesday to do this experiment as well.

You must come to class with the following information TYPED:  Refer to the pack you received in class today for the details of each section.

Planning (a):
         Question
         Hypothesis
         Variable chart


Planning (b):
        Protocol Diagram
        Procedure


Raw Data Table

Osmosis & Diffusion

Today we reviewed osmosis, diffusion and facilitated diffusion.  To see animations of each of these types of molecular movement check out these links:  osmosis, diffusion or facilitated diffusion

from: http://www.glogster.com/media/5/32/61/40/32614024.jpg

Tomorrow we will be talking about experimental design.  You will need to design an experiment that addresses the ONE of following questions:

How do different concentrations of a specific solution affect the rate of osmosis in potatoes?

OR:

How do different concentrations of a specific solution diffuse across a semi permeable membrane?

You have been emailed a series of documents (which you will also receive in class) that help you to plan out your experiment.

When you come to class tomorrow you need to have:

A hypothesis
Identified the independent variable
Identified the dependent variable
A list of things that you will need to control in this experiment

I can not emphasize this point enough:
You must complete this on your own.  You may do any research you like (CITE YOUR SOURCES!), however you can NOT work with a partner!