IE241 Problems 2

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IE241 Problems 2
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• 1. In a poll taken among college students, 46 of
  200 fraternity men favored a certain proposition,
  whereas 51 of 300 nonfraternity men favored it.
  Is there a real difference of opinion on this
  proposition?

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• 2. A test of 200 youths and 500 adults showed
  that 50 of the youths and 60 of the adults were
  poor drivers. Test the claim that the youth
  percentage of poor drivers is 10 percentage
  points higher than the adult percentage of poor
  drivers vs the claim that the youth percentage is
  more than 10 percentage points higher than the
  adult percentage.

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• 3. Two sets of 100 children each were taught to
  read by two different methods. After the
  instruction was over, each class took a reading
  test. For group A, the mean 73.4 and the
  standard deviation 8. For group B, the mean
  70.3 and the standard deviation 10. Is there a
  difference between the two teaching methods?

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• The number of individuals possessing the four
  blood types should be in the proportions
  q2p22pqr22qr2pr
• Given the observed frequencies,
• 180, 360, 132, 98,
• test for compatibility with p .4, q
  .4, r .2.

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• 5. A new drug claims to be effective in curing
  colds. In an experiment on 164 people with
  colds, half were given the drug, and half, a
  placebo. Is the drug effective if the results
  were

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• 6. Given that X is normally distributed, assume
  that the results of a sample of size 20 had a
  mean 42 and s 5. (a) Test the hypothesis
  that s 8. (b) Test the hypothesis that µ 45.

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• 7. Two random samples are taken from two
  normal populations. Test the hypothesis that µ1
  µ2. Make sure that your test is valid.

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• 8. The following data give the protein gains of
  20 rats. Half of them received their protein
  from raw peanuts and the other half, from roasted
  peanuts. Test to see whether roasting the
  peanuts had any effect on protein value.
• Is the test valid?

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• 9. The following table gives data on the
  hardness of wood stored outside and inside. Test
  to see if the variability of hardness is affected
  by weathering.

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• 10. Coated and uncoated steel pipes were tested
  for corrosion effects. The results are shown in
  the table below.
• Test the hypothesis that the difference
  between the means 0. Then find the 95
  confidence interval for the difference between
  the means.

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• 11. A thousand people were classified by gender
  and color-blindness, with results as shown below.
  Are gender and color-blindness independent?

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• 12. Twelve pairs of runners have been matched
  with respect to ability. Each member of a pair
  is given a pill before the race. One member of
  each pair is given a stimulant in his pill, but
  the other is not. Each runner runs a race and
  the times are recorded below. Is the stimulant
  effective? Compute a 95 confidence interval for
  the difference between the means.

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• 13. In an industrial experiment, the time needed
  to do a job by method 1 was compared with the
  time needed to the same job by method 2. Given
  the times shown below, is method 1 better than
  method 2? If so, do a 95 confidence interval
  on the time difference.

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• 13.