{"id":4450,"date":"2014-01-30T16:09:24","date_gmt":"2014-01-30T22:09:24","guid":{"rendered":"https:\/\/www.kabt.org\/?p=4450"},"modified":"2014-01-30T16:54:44","modified_gmt":"2014-01-30T22:54:44","slug":"day-47-48-im-95-confident-freshman-can-do-statistics","status":"publish","type":"post","link":"https:\/\/www.kabt.org\/?p=4450","title":{"rendered":"Day 47-48: I’m 95% Confident Freshman Can Do Statistics"},"content":{"rendered":"

Back again for fun and frivolity.<\/p>\n

Monday, my students were examining their mounted slides (made previously<\/a>) of their embryos from their\u00a0Tep3\/cyoYFP\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em>x\u00a0Tep3\/cyoYFP\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>cross. 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% of their offspring die as embryos, which they were thinking would happen in 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>individuals. The 25% would come from just the\u00a0cyoYFP\/cyoYFP<\/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>\u00a0dying and the 50% would be if the\u00a0Tep3\/<\/em><\/em><\/em><\/em><\/em><\/em>Tep3\u00a0<\/em>were dying too, along with the\u00a0cyoYFP\/cyoYFP<\/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>\u00a0individuals; the other 50% surviving would be from the\u00a0Tep3\/cyoYFP\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>individuals. So students took to their microscopes and recorded their data in a table, seen below:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Individual<\/td>\nA\/P Normal<\/td>\nDenticle Belts Present<\/td>\nEarly Lethal<\/td>\nNotes<\/td>\nSlide Number:<\/td>\n<\/tr>\n
1<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\nDate:<\/td>\n<\/tr>\n
2<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\nScored by:<\/td>\n<\/tr>\n
3<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
4<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
5<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The A\/P normal refers to organisms the appeared to have normal development of anterior and posterior portions, a first step for determining lethality. Then they checked for denticle belts (see Figure A and B below) which are easily seen in developmentally normal\u00a0Drosophila<\/em>\u00a0and could also determine defects. The early lethal column was where students determined if after those 2 checkpoints if the embryos were dead before mounting. Those organisms looked like opaque embryos (compared to dark) and did not display normal signs of A\/P or denticle belt development (such as Figures C-J below).<\/p>\n

\"\"<\/a><\/p>\n

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\n\n\n\n\n\n\n\n\n\n
Outcomes<\/td>\nObserved (O)<\/td>\nExpected (e)<\/td>\no-e<\/td>\n(o-e)^2<\/td>\n(o-e)^2)<\/td>\n(o-e)^2)\/e<\/td>\n<\/tr>\n
Alive<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
Dead<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

They 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>\n

Interesting…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:\"\"<\/p>\n

***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,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_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":[],"_links":{"self":[{"href":"https:\/\/www.kabt.org\/index.php?rest_route=\/wp\/v2\/posts\/4450","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kabt.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kabt.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kabt.org\/index.php?rest_route=\/wp\/v2\/users\/5582"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kabt.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4450"}],"version-history":[{"count":3,"href":"https:\/\/www.kabt.org\/index.php?rest_route=\/wp\/v2\/posts\/4450\/revisions"}],"predecessor-version":[{"id":4453,"href":"https:\/\/www.kabt.org\/index.php?rest_route=\/wp\/v2\/posts\/4450\/revisions\/4453"}],"wp:attachment":[{"href":"https:\/\/www.kabt.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4450"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kabt.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4450"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kabt.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4450"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}