Download presentation
Presentation is loading. Please wait.
1
Today: Chi 2, Inquiry 2 and Lab Safety... http://www.eurofins.com/media/19528/es_breda_lab_overview.jpg
2
The Chi Square Test A statistical method used to determine goodness of fit – Goodness of fit refers to how close the observed data are to those predicted from a hypothesis
4
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Two flies with different traits are bred together Out of 352 offspring 193 straight wings, gray bodies 69 straight wings, ebony bodies 64 curved wings, gray bodies 26 curved wings, ebony bodies
5
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display According to our hypothesis, there should be a 9:3:3:1 ratio of fly offspring Phenotype Expected probability Expected number straight wings, gray bodies 9/169/16 X 352 = 198 straight wings, ebony bodies 3/163/16 X 352 = 66 curved wings, gray bodies 3/163/16 X 352 = 66 curved wings, ebony bodies 1/161/16 X 352 = 22
6
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Apply the chi 2 formula
7
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Interpret the chi square value The calculated chi square value can be used to obtain probabilities, or P values, from a chi square table These probabilities allow us to determine the likelihood that the observed deviations are due to random chance alone If the chi square value results in a probability that is less than 0.05 (ie: less than 5%) The hypothesis is rejected
8
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Interpret the chi square value Before we can use the chi square table, we have to determine the degrees of freedom (df) The df is a measure of the number of categories that are independent of each other df = n – 1 where n = total number of categories In our experiment, there are four categories Therefore, df = 4 – 1 = 3
9
1.06
10
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Interpret the chi square value With df = 3, the chi square value of 1.06 is slightly greater than 1.005 (which corresponds to P= 0.80) A P = 0.80 means that values equal to or greater than 1.005 are expected to occur 80% of the time based on random chance alone Therefore, it is quite probable that the deviations between the observed and expected values in this experiment can be explained by random chance
11
Spreadsheet applications will compute chi 2 Is the male:female ratio in the CNS different from the general population?
12
Inquiry 2 -Who? Groups of 3-5 people
13
Inquiry 2 -Who? Groups of 3-5 people Divide work
14
Inquiry 2 -Who? Groups of 3-5 people Divide work Be clear about responsibilities and expectations Leave enough time to get everything done without panic
15
Inquiry 2 -What? Incredibly, amazingly, fantastically, critically important, essential information has been posted on the class webpage and the FRI-rm webpage (https://fasttex.diia.utexas.edu/fri-rm) about: Lab Safety Supplies Order Forms Updated Proposal and Report Formats
16
Inquiry 2 -What? May use gadgets, chemicals, kits, etc -https://uteach.utexas.edu/direct -Analytical/physical chemistry storeroom (order on website) -Media kitchen (via chem storeroom) -Research Streams
17
To submit an order you need to know your unique number... and
18
Your order must include disposal information.
19
CAS registry numbers: unique identifiers for most chemicals http://www.cas.org/expertise/cascontent/registry/regsys.html
20
Inquiry 2 -What can you not do? No experimental manipulations on vertebrates, observations are fine. No collection of wild-type microorganisms, bacteria and/or yeast
21
Inquiry 2 -What can you not do? No experimental manipulations on vertebrates, observations are fine. No collection of wild-type microorganisms, bacteria and/or yeast Similar limits to inquiry 1: 3 weeks from proposal to report Safety is the #1 priority
22
Inquiry 2 -Where and When? You can work in lab during your scheduled lab times, and/or during my other lab times. M 12-3pm M 3-6pm Th 12:30-3:30pm Th 3:30-6:30pm
23
Inquiry 2 -Where and When? You can work during the your scheduled lab times, and/or during my other lab times. Outside of lab times, you may only work when a TA is present. These times will be posted weekly.
24
Inquiry 2 -Where? Lab Safety
25
Inquiry 2 -Where? Lab Safety Closed toed shoes, sleeves, long pants, hair out of harms way
26
Inquiry 2 -Where? Lab Safety Closed toed shoes, sleeves, long pants, hair out of harms way NO FOOD in lab
27
Inquiry 2 -Where? Lab Safety Closed toed shoes, sleeves, long pants, hair out of harms way NO FOOD in lab Be aware of what you are doing and working with
28
Inquiry 2 -Where? Lab Safety Closed toed shoes, sleeves, long pants, hair out of harms way NO FOOD in lab Be aware of what you are doing and working with Wash hands before leave lab
29
Inquiry 2 -Where? Waste Disposal You are responsible for the safe disposal of all waste you generate. Waste disposal is one of the most dangerous things that we do in lab.
30
Inquiry 2 -Where? Waste Disposal
31
Inquiry 2 -Where? Waste Disposal You are responsible for the safe disposal of all waste you generate. This includes chemical waste and biological waste.
32
If you make a mistake, spill something, have an accident… tell someone immediately. http://www.time4science.com/images/labsafety/labsafety2.JPG
33
Inquiry 2 -How? Proposal Mostly the same as inquiry 1 2 additional parts
34
Inquiry 2 -How? Proposal Mostly the same as inquiry 1 2 additional parts In the Experiment section Include detailed information on equipment and reagents to be used. Where will you get them? After your proposal is approved, needed order forms filled out online.
35
Inquiry 2 -How? Proposal Mostly the same as inquiry 1 2 additional parts Add a Responsibilities section Describing your plan for whom will do what…
36
Inquiry 2 -How? Proposal Proposals will not be approved until sources for all equipment and/or chemicals are secured. Orders will be placed during lab, after your proposal is approved.
37
Inquiry 2 -How? Written Reports Similar to inquiry 1, but add a Responsibilities section
38
Inquiry 2 -How? Written Reports Similar to inquiry 1, but add a Responsibilities section Everyone should participate in writing, some may write the original text, while others work on figures/tables, and others edit.
39
Inquiry 2 -How? Oral Reports Should be 15 to 20 minutes long
40
Inquiry 2 -How? Oral Reports Should be 15 to 20 minutes long Include all of the basic information from the written report. (Do not simply read your written report)
41
Inquiry 2 -How? Oral Reports Should be 15 to 20 minutes long Include all of the basic information from the written report. (Do not simply read your written report) Everyone will present some part of the oral report
42
Inquiry 2 -How? Oral Reports Should be 15 to 20 minutes long Include all of the basic information from the written report. (Do not simply read your written report) Everyone will present some part of the oral report Should be visually engaging
43
My group sucks, and now I am going to fail.
44
Don’t have a cow man. Your will be graded as a group and also only on your sections.
45
Inquiry 2 proposals are due in lab on Th 9/30 or M 10/4 Homework #3 due now: What was the hardest part of inquiry 1, and how will you make this easier for inquiry 2? This weekend: Pecan Street Arts Festival (http://www.oldpecanstreetfestival.com) Stream open house ongoing (homework #2) Next week: Research Ethicshttp://www.oldpecanstreetfestival.com
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.