Quiz 06 Normal Curves 7.3a • Name:

1. According to a study done in a rural village on Pohnpei, the mean number of hours spent on farming activities per week was = 24 with a standard deviation of σ = 8. For this exercise assume that the number of hours spent in farming was normally distributed.1

  1. p(x ≤ 24) = __________ What is the probability the number of hours spent on farming activities per week is 24 or less?
  2. p(x ≤ 16) = __________ What is the probability that the number of hours spent on farming activities per week is 16 or less?
  3. p(x ≥ 40) = __________ What is the probability that the number of hours spent on farming activities per week is 40 or more? Use Excel to answer this!
  4. p(20 ≤ x ≤ 40) = __________ What is the probability that the number of hours spent on farming activities per week is more than 20 and less than 40? Use Excel to answer this!

Normal Statistics
Calculate a z value from an x z = standardize.gif (905 bytes) =STANDARDIZE(x, , σ)
Calculate an x value from a zx = z σ + =z*σ+
Find a probability p(x) from a z value where the probability p is the area to the left of z. =NORMSDIST(z)

normal curve areas

1 Based loosely on data from a study done by Sarah Schaeffer, Emory University.

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