Stat 202: Lecture 14 (covers pp. 160-165)

Nathan VanHoudnos
10/27/2014

Agenda

  1. Midterm (test and quarter!) comments
  2. PSA
  3. Lecture 14 (covers pp. 160-165)

Midterm distribution

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mean(midterm)
[1] 63.5493
median(midterm)
[1] 64

Midterm distribution

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Percent of the class with a \( X \) or above:

     [,1]     
[1,] "A   11%"
[2,] "B   25%"
[3,] "C   41%"
[4,] "D   58%"

Course grade distribution

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After dropping

  • 3 lowest checkpoints
  • 1 lowest homework
     [,1]     
[1,] "A   23%"
[2,] "B   62%"
[3,] "C   89%"
[4,] "D   94%"

No “curve” is needed.

Question Breakdown

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Questions 4 and 5 differentiated the class.

  • Homework 4 score had very little power to predict performance
  • Time seemed to be an issue for some students
  • Many students were simply wrong.

Moving Forward

Mid-Quarter Grades plot of chunk unnamed-chunk-8

  • To determine final exam length I will triple the time it took me instead of doubling it.

  • You will see something like Q4 and Q5 on the final.

  • The final Q4 and Q5 can replace the midterm Q4 and Q5 scores.

Agenda

  1. Midterm (test and quarter!) comments
  2. PSA
  3. Lecture 14 (covers pp. 160-165)

PSA - Office hours

I need to cancel my office hours this week.

  • If you need to meet with me, as always, feel free to send me an email.

  • Aaron will still hold his office hours on Thursday.

  • (For that matter send Aaron email if you can't make his either.)

PSA - Intersex Awareness day

From Emily Quinn (Animator for Adventure Time):

Being intersex means that you were born with differences in your sexual characteristics — these differences can affect genes, chromosomes, genitalia, reproductive organs, hormones and also things like body hair and how much you sweat.

  • Quinn's AMA on reddit (yesterday).

  • Surprising Fact: Intersex is as common as being a natural redhead (1/20,000).

  • For pedagogic reasons, Stat 202 gender is binary.

Agenda

  1. Midterm (test and quarter!) comments
  2. PSA
  3. Lecture 14 (covers pp. 160-165)

Height of Adult males

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Assume that the height of adult men is normally distributed with a mean of 69 in. and a standard deviation of 2.8 in.

Height of Adult males

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Assume that the height of adult men is normally distributed with a mean of 69 in. and a standard deviation of 2.8 in.

  • Randomly select 15 men from the population and measure their heights:
67.2 69.5 66.7 73.5 69.9 66.7 70.4 71.1 70.6 68.1 73.2 70.1 67.3 62.8 72.1

Height of Adult males

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Assume that the height of adult men is normally distributed with a mean of 69 in and a standard deviation of 2.8 inches.

  • Randomly select 15 men from the population and measure their heights:
  • Make a histogram of those randomly selected 15 men.

Height of Adult males