After they determined this we created a class-wide spreadsheet that students imputed the number of alive vs. dead embryos they started with\/counted. That was Monday.<\/p>\n
Then Monday night I got a weird idea…<\/p>\n
…what if I tried teaching my freshman some statistics?*<\/p>\n
Obviously our question from Monday, “Are 25% or 50% of our embryos dying?” begged for some statistics, and pretty common ones too. We have data of how many embryos lived or died and we have a question that asks do our results closely match 25% or 50% lethality? Is our 35% close enough to 25% or 50%? (There were differing opinions in the room: talk about entry points, they needed no help randomly suggesting whether they felt 10% or 15% off from a value was of significance to them) I then said we have a test to determine significance in our data. We need Chi-Square!** (At this point, I would like to acknowledge, that given time I would have loved to run through Brad’s chi-square excel model with them [check the AP Discussion Board], but we did not have the chance. Maybe later. That was just a plug for a great student exercise)<\/p>\n
So, I presented the problem to them again, this time with our data. (Let’s say 350 dead out of 1,000 embryos just as an example) I asked them if 50% were dying due to the\u00a0Tep3\/<\/em><\/em><\/em><\/em><\/em><\/em>Tep3\u00a0<\/em>and\u00a0cyoYFP\/cyoYFP\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>mutation, how many of the 1,000 embryos would we expect to be dead? Of course, 500. Then I asked, “Ok, how off or “different” from that 500 are we for both the dead and alive organisms?” At this point I told them it might be easiest to set up a table. So they set up a table with a 3 rows and initially 3 columns. Eventually, they created this.<\/p>\n\n\n\nOutcomes<\/td>\n Observed (O)<\/td>\n Expected (e)<\/td>\n o-e<\/td>\n (o-e)^2<\/td>\n (o-e)^2)<\/td>\n (o-e)^2)\/e<\/td>\n<\/tr>\n \nAlive<\/td>\n <\/td>\n <\/td>\n <\/td>\n <\/td>\n <\/td>\n <\/td>\n<\/tr>\n \nDead<\/td>\n <\/td>\n <\/td>\n <\/td>\n <\/td>\n <\/td>\n <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\nThey knew observed and expected pretty easily and finding the difference between the two. Because this gives them negative values I asked them are we looking for magnitude of difference or general significant vs. non-significant? Again, we decided negative values aren’t telling us too much, so I introduce the squaring idea. We then divide by e (I had no idea how to explain this principle to students. I think e is also variance squared but this concept would destroy their minds, so I’m not sure how much of a disfavor I did to students by not explaining this)<\/p>\n
Either way, we got significant results for both the 50% and 25% (Yes, I made some students who didn’t pass out do both***) which told us that our data was not close enough to 25% or 50% to be just random coincidence. Something else is at play in our research. We know\u00a0cyoYFP\/cyoYFP\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>individuals die, because inheriting two balancer chromosomes is lethal. So what’s up with our\u00a0Tep3\/<\/em><\/em><\/em><\/em><\/em><\/em>Tep3\u00a0<\/em>mutation? Apparently, it is causing death in embryos, but not all, and larva, but not all.<\/p>\nInteresting…sounds like an experiment.<\/p>\n
*Turns out if you Google “teaching freshman statistics” you get a bunch of college results back. Changing it to “teaching high school freshman statistics” only gave me more college results. Google never listens to me.<\/p>\n
**They reacted something like this:
***Hey, the ones who did it twice loved it.<\/p>\n","protected":false},"excerpt":{"rendered":"
Back again for fun and frivolity. Monday, my students were examining their mounted slides (made previously) of their embryos from their\u00a0Tep3\/cyoYFP\u00a0x\u00a0Tep3\/cyoYFP\u00a0cross. They were collecting data on how many of their embryos died (obviously before we bleached and mounted them) and how many survived. This was a test to see if they saw 25% or 50%+ Read More<\/a><\/p>\n","protected":false},"author":5582,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_s2mail":"yes","_uf_show_specific_survey":0,"_uf_disable_surveys":false,"footnotes":""},"categories":[9,38],"tags":[],"class_list":["post-4450","post","type-post","status-publish","format-standard","hentry","category-labs","category-student-research-ideas"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t
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