Correcting

Exercise

Introduction


Sometimes lecturers will make a mistake and correct themselves.

Phrases they could use include:

  • sorry
  • oops/whoops/woops
  • I got that wrong/made a mistake
  • my mistake/fault/bad
  • I mean/what I meant
  • I should have said
  • or rather

Examples

  • We have a plus 1 times n, so let’s write it 1 minus c_2 over 2 times n. Oops, got that wrong.
  • Oops, look what I did.  I forgot the d/dt in front of the integral sign.  Sorry for that.
  • It’s one over s, except it isn’t. I made a mistake. Well, not mistake, a little oversight.
  • I’ve just expressed it in degrees Kelvin. Sorry. My mistake. Excuse me.
  • It’s the denominators, that’s what I did wrong. Right, so it is pm over pp. Sorry, my  bad.
  • In the middle here is sitting Q Q t- Q transpose Q, sorry, that’s what I meant to say, Q transpose Q is I.
  • You’re right. That’s an excellent point that I should have pointed out.
  • Determinate of A transposed equals determinate of A. That’s what I should have said. OK.
  • Sorry, I forgot to mention that.
  • So, what is the first, woops, I forgot a bracket.
  • I’ll put this one up in blue to indicate that it’s bad. Whoops, sorry, I mean, not really bad, but recalcitrant.
  • This is a pipeline picture of an MPEG 2 decoder or rather a blocked level diagram of an MPEG 2 decoder.
  • Well, you’re in some battle, or rather, your troop is in some battle, and people are being killed left and right.
  • How do you spell cocoon? That’s not right.

Gap fill

  1. You can never say I don’t know, I don’t know which I prefer, I’m indifferent. I’m sorry, let me back up. I’m using the wrong word. Forget I said indifferent, because we’ll want to use that word in a different context later. You can’t say, I’m not sure. You can’t say, I’m not sure. You can’t say, I’m not sure, you can’t say I don’t know, I don’t know how I feel about that. Completeness means that, uh – I’m sorry, I messed this up. So just scratch what I said a few minutes ago, because I want to use indifference differently.
  2. Now given these, we’re going to talk about the properties of what we call indifference curves. This is why I screwed up before. Of course you can be indifferent between things. That’s the whole point of economics. I don’t know why I got that wrong. I haven’t taught this course in about six years, so I lost track of things.
  3. And to show that, let’s look at figure 4-3 which isn’t here. Whoops. There’s no figure 4-3. Did you get that figure 4-3? There was never any figure 4-3. OK, great. So let’s go to 4-5. So basically – No, but let’s just – actually fine. 4-4. So basically what this is showing, what figure 4-4 is showing, is it’s showing how – no actually, let’s go to 4-5. They’re out of order. Let’s go to 4-5. What 4-5 is showing – no, that’s not going to work. OK, back to 4-4. What figure 4-4 is showing, is it’s showing how your marginal utility for movies evolves, how your utility evolves as you get more movies.
  4. Utility is going to increase – I’m doing this wrong, hold on. One second. From one movie. I see. I see. So, I’m sorry. This isn’t the delta, this is the level of marginal utility. So I’m graphing the actual level of marginal utility. Back up. OK, so I’m graphing the actual level of marginal utility.
  5. So the very first movie gives you marginal utility of 1.4 because you go from 0 to square root of 2. That’s right. My bad.
  6. Oh, yes. Thank you. I have a type error. Sorry about that. F of n is indeed the upper left corner, I hope. I better check I don’t have it off by one. I do. It’s F_n upper right corner, indeed. That’s what you said. F of n. I need more space. Sorry. I really ought to have a two-by-two matrix on the left-hand side there. Thank you.
  7. And that is itself [(1, 1), (1, 0)]. And I should have said n is at least 1.
  8. This is a good old-fashioned calculator. No, that is wrong. Sorry. It is strictly less than 2.81.
  9. 10 to the negative – sorry, this is wrong. 10 to -5. Thank you.
  10. Now, there was some confusion because while I described these two air masses moving northward and southward, in the end I said how much heat is transported northward. What I meant to say, what I hoped you would interpret that is the net amount transported northwards.
  11. Now, for the temperature itself, you can’t read the labels very well, but some of these are slightly negative, temperature of minus 0.02 — sorry 0.2 or 0.4.
  12. There’s a tongue. Apparently a water mass is being formed here in the Antarctic Ocean – so sorry, in the southern Ocean. Not close to the shores of Antarctica, but in the Southern Ocean.
  13. Organisms use – as soon as the water leaves – I should have said this, thanks Julia – as soon as the water leaves the surface it begins to lose oxygen because animals use it up, and respiration takes place to use up the oxygen. So the older the water is, the less oxygen it has in it.

Transcript

  1. You can never say I don’t know, I don’t know which I prefer, I’m indifferent. I’m sorry, let me back up. I’m using the wrong word. Forget I said indifferent, because we’ll want to use that word in a different context later. You can’t say, I’m not sure. You can’t say, I’m not sure. You can’t say, I’m not sure, you can’t say I don’t know, I don’t know how I feel about that. Completeness means that, uh – I’m sorry, I messed this up. So just scratch what I said a few minutes ago, because I want to use indifference differently.
  2. Now given these, we’re going to talk about the properties of what we call indifference curves. This is why I screwed up before. Of course you can be indifferent between things. That’s the whole point of economics. I don’t know why I got that wrong. I haven’t taught this course in about six years, so I lost track of things.
  3. And to show that, let’s look at figure 4-3 which isn’t here. Whoops. There’s no figure 4-3. Did you get that figure 4-3? There was never any figure 4-3. OK, great. So let’s go to 4-5. So basically – No, but let’s just – actually fine. 4-4. So basically what this is showing, what figure 4-4 is showing, is it’s showing how – no actually, let’s go to 4-5. They’re out of order. Let’s go to 4-5. What 4-5 is showing – no, that’s not going to work. OK, back to 4-4. What figure 4-4 is showing, is it’s showing how your marginal utility for movies evolves, how your utility evolves as you get more movies.
  4. Utility is going to increase – I’m doing this wrong, hold on. One second. From one movie. I see. I see. So, I’m sorry. This isn’t the delta, this is the level of marginal utility. So I’m graphing the actual level of marginal utility. Back up. OK, so I’m graphing the actual level of marginal utility.
  5. So the very first movie gives you marginal utility of 1.4 because you go from 0 to square root of 2. That’s right. My bad.
  6. Oh, yes. Thank you. I have a type error. Sorry about that. F of n is indeed the upper left corner, I hope. I better check I don’t have it off by one. I do. It’s F_n upper right corner, indeed. That’s what you said. F of n. I need more space. Sorry. I really ought to have a two-by-two matrix on the left-hand side there. Thank you.
  7. And that is itself [(1, 1), (1, 0)]. And I should have said n is at least 1.
  8. This is a good old-fashioned calculator. No, that is wrong. Sorry. It is strictly less than 2.81.
  9. 10 to the negative – sorry, this is wrong. 10 to -5. Thank you.
  10. Now, there was some confusion because while I described these two air masses moving northward and southward, in the end I said how much heat is transported northward. What I meant to say, what I hoped you would interpret that is the net amount transported northwards.
  11. Now, for the temperature itself, you can’t read the labels very well, but some of these are slightly negative, temperature of minus 0.02 — sorry 0.2 or 0.4.
  12. There’s a tongue. Apparently a water mass is being formed here in the Antarctic Ocean – so sorry, in the southern Ocean. Not close to the shores of Antarctica, but in the Southern Ocean.
  13. Organisms use – as soon as the water leaves – I should have said this, thanks Julia – as soon as the water leaves the surface it begins to lose oxygen because animals use it up, and respiration takes place to use up the oxygen. So the older the water is, the less oxygen it has in it.

Video sources

  • Jonathan Gruber, Principles of Microeconomics, Fall 2011 (Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed 3 June 2013). Licence: Creative Commons BY-NC-SA
  • Charles Leiserson and Erik Demaine, Introduction to Algorithms (SMA 5503), Fall 2005 (Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed 3 June 2013). Licence: Creative Commons BY-NC-SA
  • Ronald B. Smith, The Atmosphere, the Ocean, and Environmental Change (Yale University: Open Yale Courses), http://oyc.yale.edu (Accessed 3 June 2013). Licence: Creative Commons BY-NC-SA. Terms of Use