Lesson 8: Normal Curves

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September 13, 2016 at 7:53 pm  •  Posted in f16-busad265 by  •  0 Comments

Wed, Sep 14

Review:

Presentation:

  • Density Curves
    • Height of curve indicates proportion of values
    • Area under the curve = 1.0
      • Any sub-area under the curve is then a proportion (% of values)
  • Normal Curves
    • A special case of density curves
    • Bell shaped and symmetrical
    • Mean and Standard deviation
    • 68 – 95 – 99.7 Rule
    • Video

Activity:

  • Problem 1.
    • Height of 4-year-old boys is approximately normally distributed with mean 40 inches and standard deviation 1.5 inches.
      • Draw a normal density curve and label the mean on the horizontal axis.
      • Also mark points on the horizontal axis one standard deviation on either side of the mean.
  • Problem 2.
    • IQ scores are normally distributed with mean 100 and standard deviation 15. Scores from 90 to 110 represent normal or average intelligence. Scores above 120 represent superior intelligence.
      • Draw a normal density curve for IQ scores.
      • Label the mean and one standard deviation on either side of the mean.
      • Shade the area under your normal curve that represents the proportion of people with normal intelligence.
      • Then shade, in a different way, the area representing the proportion of people with superior intelligence.

Assignment:

  • Read pp. 53-61 Density Curves and Normal Distributions
  • Complete the Use Your Knowledge questions 1.99 and 1.100 on pp. 60-61

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