“Teach me,” she said.

[America]

British authorities were not counting deaths by head wound as "wounds". Deaths went way down and survived "wounds" went way up.

[Cen]

Since your reply goes to the next page its a perfect reveal of the right answer. Its a question based on a concept of "survivorship bias". Its great to throw at statistics people because it will be almost insultingly easy for them to see, but theres no shame in having great difficulty in it, because survivorship riddles have historically confused some of the greatest minds.

[Cecily]

I had great difficulty understanding the question because it’s the first thing I read when I woke up. Huh, they made helmets out of old shrapnel? Lol. That was illiterally how I was tying to solve it.

I wish it was blatant to me, but I might have missed this one. Thank you for sharing that. It’s a good lesson on why looking at data (and probably things in genral) from a variety different view points is necessary because the obvious conclusion might be the wrong one, no matter how many people believe it.

Gonna look that bias up now.

[Cecily]

^ Looked into that some more. Really good thing to keep in mind, ty.


So, tonight I learned I don't know how to do logarithms anymore.


What is the generation time of a bacterial population that increases from 10,000 to 10,000,000 cells in four hours of growth?



a = number of bacteria at the beginning of a time interval. A = number of bacteria at the end of the time interval


G= T
3.3log a/A


G= T
3.3log 10^7/10^4


G = 240 mins
3.3 x 3


G = 24 mins




Ok. NM. Pretty sure in the past I'd do logarithms by asking lab partner what they got, but it just looks like enter number and press button ??? answer.

[Cecily]

Logarithm quotient rule

The logarithm of the division of x and y is the difference of logarithm of x and logarithm of y.
logb(x / y) = logb(x) - logb(y)


so 10^7 = 10,000,000 = log 7
10^4 = 10,000 = log 4


log 7 - log 4 = log 3


Not sure what the (3.3 x) refers to but just taking their word for it


3.3 x 3 = 9.9


240/9.9 = 24 and change rounded down


I'm starting to figure this out but god dammit logs hurt my head.



Control
500 ml of cottage cheese was inoculated with a 2 ml culture of Pseudomonas aeruginosa and incubated at 25°C. Five hours after inoculation, in a standard plate count there were 200 bacterial cells/ml. After 29 hours at 25°C, there were 1,000,000 cells/ml.


Experiment
500 ml of cottage cheese containing the preservative was inoculated with a 2 ml culture of Pseudomonas aeruginosa. After 6 hours of incubation at 25°C, a standard plate count was performed. There were 700 bacterial cells/ml. After 38 hours, there were 61,000,000
bacterial cells/ml.


Number Log
1 0.00
2 0.30
5 0.70
6 0.78
24 1.38
32 1.51
200 2.30
700 2.85
1.00 × 106 6.00
6.10 × 106 6.79
6.10 × 107 7.79

[Cecily]

1. Why were plate counts used for analyzing bacterial growth instead of direct
microscopic counts or turbidity measurements?

Because it's an experiment over an extended period of time, plate counts would be ideal. The control concentration is too low for turbidity (about 10 - 100 million / mL) and microscopic counts (>10 million / mL), Also, turbidity and microscopic counts have trouble distinguishing live cell counts from dead cell counts. Yet another reason would be the live organism is most likely motile and therefore hard to count with a microscope.



2. How did the control cottage cheese and the experiment cottage cheese differ? What was the independent variable and dependent variable? (Hint: Scientific method)

Independent variable = preservative
Dependent variable = generation time


* I think that's right? It's been a long time since elementary school science.
"The independent variable is the one the experimenter controls. The dependent variable is the variable that changes in response to the independent variable."



3. Determine the effectiveness of the new food preservative by calculating the
generation time of bacterial population in the control versus the experimental
cottage cheese.



Experimental
End: 6.10 x 10^7 = log 7.78
Begin: 700 = log 2.85


G = t/3.3 x log (log 7.78 - log 2.85)
G = t/3.3 x 4.93
G = t/16.269
t = 38 hours x 60 = 2280 mins / 16.27 =
Experimental G = 140 mins

Control
End: 1,000,000 = 1.00 x 10^6 = log 6
Begin: 200 = log 2.30

G = t/3.3 x log (log 6 - log 2.3)
G = t/3.3 x log 3.7
G = t/12.21
t = 29 hours x 60 = 1740/12.21
Control G = 143 mins


Conclusion: The preservative was marginally successful in inhibiting microbial growth.



4. Does this type of test determine bacteriostatic or bactericidal activity?

The goal of a food preservative is to inhibit bacterial growth, not necessarily kill bacteria, so this test would determine bacteriostatic activity.


Pretty sure that's right. Haven't encountered those definitions in any chapter reading yet.




Finally done.

[Cecily]

Fixed some errors in that ^

This should be useful. Got a can you do math test coming up sometime soon for nursing program. ATM, no lol.

General Math Tables:
https://www.rapidtables.com/math/alg....html#ln-rules


Remedial Math Tutorials:
Dimensional Analysis
Graphing Oscillating Fns.
Trigonometry
Graphing Simple Fns.
Graphing Log Paper
Logarithms
Algebra
Vectors
Unit Conversions
Significant digits

[Vormotus]

Originally Posted by Cecily [You must be logged in to view images. Log in or Register.]

So to start this off, I’ve taken a statistics class years ago at a 4y college and all I learned was how to input numbers into a program. I’d really like to relearn the useful information to help me understand research journals, but for now I have a question about calculating percentile rank.

I have data for 5th%, 95th%, mean, and total number.

Can I use this information to plug in a number to determine its percentile rank?

Ex:
My weight = 196 lbs
Mean = 153.2 lbs
5th percentile = 105.5 lbs
95th percentile = 225.6 lbs
N = 8764

How do I figure out my rank?

Using data from this table:
http://andreaportman.tripod.com/averages.html

You know, sober I might have given you a solid answretr, see I am a colege degree Psychologist, I had during my 5 years course , over 8 tipes of statistcs , like introduction to statistics, advanced statistics I 2 and 3 and then we have Psychodinamic Statistis 1 and 2 and another i dont remember. I saw som any statistic i remember even being able to decompile MMPI and Bender tests into validates items to create new tests with a hifg degree of validation ... that stuff has server me 0% in real life.

LIKE 0% except showing off in a crap reddit thread once or twice in over a decade.

My only real input to you is to study , pass and graduate and then forget abvout everything and learn to either code, a second and third language and perhaps learn how to save money, manage a budget and then invest in either real state in emerging thrid world countries or invest in solid stock like mutuals that give above average depreciation rates of the usd so you can at least keep the same money every year over the basic inflation ratesof it.

That is the only trhing that will help you in life.

Ahh and get a sensible partner that does not waste your own resources, that is a super plus alongisde not having more than one chil dif you have as alife gfoal to reproduce your genetic line.

yep, that is the only trhing you will need to suceed at life. Please remember no corporation whatsoeves, alongside f"riends2" you might make there are really honest or real , the only people you can trust you can count on your hand and have fingers left to count.

Also never ever tell anyone what you really own, or how much money you make. fact is, I have foudn if you portray yourself as poor you will usually get more out of people, as they will either ignore you or dismiss you as non threatening

what else? yep, never buy a car because its fancy or represent you, cars are the worst investment of your money due to their depreciation rate never buy fancy clothes of items to show you are well, that is literally wasting money only to show people, that do not really care about you you are better than them, that is a total watse of your money and time.

hmmmm yeah, my granny alwaysd told me you had to be aware of your surroundings, have spatial awareness of where you are all the time. this might save your life.

if possible and in theus, learn to do CPR, and how to fire common guns, or how to disarm or descalate situations yes.


be aware protecting your honor is bullshit if it might entail losing your life, everyone else is apotential enemy during thesesituations and though yo might have enough courage, if they outnumber yu it is a losing game.

Learn how to avoid conflict with strangers, do not drink un unsafe space and enjoy small things, like friendship and family.

yep, this is the same adive I would give t my dead son. yep.

hope it helps you man or woman.

be safe always and never worry too much about people, they will never be there when needed, and those that are, cherish themlike gold!

Much love to you my friend!

[Cecily]

I’m trying to be a psych nurse, so learning how to deescalate conflict and CPR on my to do list for sure. Thank you for the advice!

Much love and respect to you.

[Cecily]

Studied micro lab tests from 7am to 2pm today, covered everything we did so far. Put a couple hours in at the Anatomy & Physiology open lab today. Made a new friend who has a suspiciously similar coloration as me. She looks really good in bright red lipstick, but pronouces her name wrong so I dunno. Still have 5.5 lab reports to write by tomorrow morning or -20 out of 1000ish total points for lab grade. Wonder if that’s worth my sleep? Probably.

Lab quiz tommorow.
Lab review on Tuesday for A&P, have two open lab sessions on Monday and Thursday I need to go to.
Bunch more micro homework for weekend.

Next week:

Monday: Micro lab midterm, 16 differential tests.
Wednesday: Micro lab exam 2, only 2 chapters on genetics, but haven’t started reading it.
Thursday: Anatomy lab midterm. 7 modules: Blood/blood tests/blood typing, blood vessels anatomy/physiology, heart anatomy/physiology, EKGs, respiratory system anatomy/physiology.

Kill me now.