High school biology
- Biology overview
- Preparing to study biology
- What is life?
- The scientific method
- The scientific method
- Data to justify experimental claims examples
- Scientific method and data analysis
- Introduction to experimental design
- Controlled experiments
- Biology and the scientific method review
- Experimental design and bias
Data to justify experimental claims examples
Example questions analyzing data to justify claims in experiments.
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- Is the first statement saying, 4 minutes after they were done exercising or 4 minutes after they started exercising?(26 votes)
- Your question is on the place.
Looks like Sal meant 4 minutes of exercising, or 4 ,mnutes after exercising started - but not 4 minutes after exercising is completed.
This one is ambiguous. I was easily tricked and mispresented the graph.
In English you can say the same way and mean two different thigs. If you get question like this on your exam, make sure to do the clarification wih our professor.(19 votes)
- Is Sal confusing "after x minutes of exercising" with "x minutes after exercising"? The former implies having exercised for a certain amount of time (not having completed exercising), while the latter would mean a certain amount of time after the completion of the workout.(14 votes)
- Yes I believe he did.
He went on the graph at the "during exercising" period instead of the "after exercising" period.
It's "four minutes AFTER exercising" and not "after four minutes OF exercising"
Happens again in the following statement @4:17(...)(10 votes)
- i thought that an hypothesis was like could be test it multiple times see if the answer stays the same?(4 votes)
- Yes, usually it is advised to test multiple times.
This was just an example.
In this study, researchers have experimented and published with their conclusions. That's why their work must be transparent, controls, samples, method - so other researchers can reproduce and test it themselves.
In some cases, it would be too expensive and time-consuming to repeat over and over again am an experiment. Especially if researchers are working on developing a new drug and need results as soon as possible.
How do you overcome that 'lack' of repeating? By taking large enough sample, having controls, etc.(3 votes)
- I didn’t understand no.3 & no.4... can we also not use the chart?(3 votes)
- No. You cannot check whether it is true or not without a graph. You need to see the graph to check for the highest rate, and pulse rate before exercising (number 4).
Why do you think you are confused? Tell me what is on your mind.(2 votes)
- Is Sal confusing "after x minutes of exercising" with "x minutes after exercising"? The former implies having exercised for a certain amount of time (not having completed exercising), while the latter would mean a certain amount of time after the completion of the workout.(3 votes)
- https://www.khanacademy.org/science/high-school-biology/hs-biology-foundations/hs-biology-and-the-scientific-method/v/data-to-justify-experimental-claims-examples?qa_expand_key=kaencrypted_f0389a037d1cd2ac4eeb91476f2046c0_be3e5a7f3968dd1e40036e7ac9ab3ce4b3b079d1d2cd994f8925e3383e7b6f88ba189b96360930c00d84c965946eb3e53014577f48c836f599cbc6fda95f41eec6bb9612a91e89c26239bd20ed49bce0eb4941d119496490062a5f5824e9944ae97de4feb82b631abc7e7abc779a9420878b014229d881d4ef60e60e5caf396f8989c3f8ae809679ecd4c798fd1929681d367eaca4017fd9351448523bef8711d7948bb3a81c827601a074791600d1f6ebe93cd51120c76fdf7badde9c19852b(1 vote)
- for the 2nd choice doesn't it mean 2 minutes after exercising(2 votes)
- ¿La primera declaración dice 4 minutos después de que terminaron de hacer ejercicio o 4 minutos después de que comenzaron a hacer ejercicio?(2 votes)
- Imagine khan academy was a physical school(2 votes)
- how does Data justify experimental claims? Why is it important?(1 vote)
- According to my calculations, the difference between the two trials is two small to support the student's claim at0:16.(1 vote)
- [Instructor] What we have here are a few data analysis questions in a biology context from the New York Regents Exam, but these are useful example problems if you're studying high school biology in general because they might show up in some type of an exam that your teacher gives you or you might see on a standardized test. A student proposes that, if volunteers warm up before squeezing a clothespin for one minute, they will increase the number of times that they can squeeze it within tiring. He states that this is because their muscles will be better prepared for the exercise. The data from an experiment are shown in the data table below. Which trial from the chart above provides the best data to support his claim? Support your answer. So, pause this video and see if you could answer it. So, let's just make sure we understand what's going on here. So, there's two trials. This is the first trial, trial one, right over here, and in trial one, you had two groups of 10 students. One of them did warm up and the other 10 did not warm up, and then in trial two, you had two more groups and this time, they were groups of 25. Once again, 25 who did warm up and 25 who didn't warm up. Now, in trial one, the group that warmed up actually had a lower number of average squeezes, so this goes against the hypothesis that the student had. The hypothesis the student has is if they warm up beforehand that you would actually be able to do more squeezes, so trial one actually goes against the student's claim. Trial two seems to slightly go in favor of the student's claim. The group that warmed up was able to eke out a few more. Now, we haven't done the statistical analysis to know how probable this is, if it was due purely to random chance, but just to answer that question, one, the data goes, trial one goes a little bit against the student's claim. Trial two best supports this claim, although it doesn't do it so strongly. So, I would say trial two and that is because the 25 that warmed, warmed up, that is group three, group three, were able, on average, on average, to squeeze more in a minute, to squeeze more in the minute than group four that didn't warm up. Alright, let's do another question here. So, here we're told, students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph below. And then they say, which statement is best supported by this graph? And we're given four choices. So, pause this video and see if you could answer this on your own. Alright, now let's go through statement by statement. Statement one, before exercising, the average pulse rate was 65. Four minutes after exercising, the average pulse rate was 65. So, let's see. Before exercising, the average pulse rate was 65. So, before exercising, this is time period right over here and it does look like over most of that time period, let me do this in red, it does look like that is reasonably, that is roughly true. It looks like the average pulse rate was 65, but now let's read the second part of the statement. Four minutes after exercising, the average pulse rate was 65 as well. Four minutes after exercising, what's the average pulse rate? Well, it sure isn't 65, it looks closer to being, maybe, 135, not 65, so we could rule this one out. After four minutes of exercising, the average pulse rate was 120. Let's see. So, this is when the exercise starts. After four minutes, the average pulse rate was 120. No, it looks like it was like 135 or something like this, so this is already looking fishy. Two minutes after exercising, the average pulse rate was 120. So, two minutes after exercising, the average pulse rate actually seems closer to about 90, so both of those look fishy, I'll rule that one out. While exercising, the average, the highest average pulse rate was 150. Before exercising, the average pulse rate was 65. So, let's see, while exercising, the highest average pulse rate happens right over there and that does indeed look pretty close to 150, so this part's looking good. Before exercising, the average pulse rate was 65. Yeah, we already talked about this period right over here. So, this is looking good, I'm liking this choice, but let's see choice four. Two minutes before exercising, the average pulse rate was 80. So, two minutes before exercising, this is when we start exercising and each of these hash marks is a minute, so two minutes before, the average pulse rate was not 80, so that's false. After two minutes of exercise, the average pulse rate was 140. After two minutes, the average pulse rate was also not 140, so both of those statements are not correct. So, I like statement three, that's the one that seems to be backed up by the data here.