Stat 202: Lecture 15 (covers pp. 171-187)

Nathan VanHoudnos
10/31/2014

Agenda

  1. Checkpoint #17 comments
  2. Lecture 16 (covers pp. 171-187)

Checkpoint #17

What is the average percentage correct for this activity?

  • 60% correct

Question 1 Checkpoint #17

Which of the following statements about the sampling distribution of the sample mean, x-bar, is not true?

  • a) The distribution is normal regardless of the shape of the population distribution, as long as the sample size \( n \) is large enough.
  • b) The distribution is normal regardless of the sample size, as long as the population distribution is normal.
  • c) The distribution's mean is the same as the population mean.
  • d) The distribution's standard deviation is smaller than the population standard deviation.
  • e) All of the above statements are correct.

Question 4 Checkpoint #17

Suppose that a candy company makes a candy bar whose weight is supposed to be 50 grams, but in fact, the weight varies from bar to bar according to a normal distribution with mean \( \mu = 50 \) grams and standard deviation \( \sigma = 2 \) grams.

If the company sells the candy bars in packs of 4 bars, what can we say about the likelihood that the average weight of the bars in a randomly selected pack is 4 or more grams lighter than advertised?

  • a) There is no way to evaluate this likelihood, since the sample size (n = 4) is too small.
  • b-d) There is about a __ chance of this occurring.
  • e) It is extremely unlikely for this to occur; the probability is very close to 0.

Agenda

  1. Checkpoint #17 comments
  2. Lecture 16 (covers pp. 171-187)

Final part of course