STATS 250 Lecture Notes - Lecture 8: Sampling Distribution, Confidence Interval, Normal Distribution

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greenhorse700

19 Oct 2014

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STATS 250 Full Course Notes

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Population= basket of n balls, 1 ball for each unit in popul. Random sample of size n (a few balls selected from population) The sample estimate provides our best guess as to what is the value of the population parameter, but it is not 100% accurate. The few or number of standard errors we go out each way from the sample estimate will depend on how confident we want to be. The confidence level is the percentage of the time we expect the procedure to produce an interval that does contain the population parameter. Goal: we want to learn about a population proportion p . We take a random sample from the population and we estimate p with the resulting sample proportion p . Each possible random sample provides a possible sample proportion p value. (if we made a histogram of all of these possible p values it would look like the normal distribution on the previous page. )

Related Questions

An urn contains 7 white balls and 3 red balls. Three balls are selected. In how many ways can the 3 balls be drawn from the total of 10 balls.: (a) If 2 balls are white and 1 is red? (b) If all 3 ball are white? (c) If all 3 balls are red?

fuchsiamule249

2 (a) Suppose you start with one Red and one Black ball in a bag. You draw a ball at random from the bag repeatedly and look at its colour each time. After each successive draw, you double the number of Red balls and triple the number of Black balls in the bag before the next draw (eg. on the third draw there will be 4 Red and 9 Black balls in the bag). Explain why you will draw only finitely many Red balls in total with probability 1. [3 marks]

(b) In a modified game, suppose instead that for before the nth draw, you first make an n by n square arrangement of balls where the perimeter balls are all Red and any interior balls are Black ball. Thus, on the second draw there are 4 Red and 0 Black in the bag (22 in total), on the third draw there are 8 Red and 1 Black in the bag (32 in total), on the fourth there are 12 Red and 4 Black in the bag (42 in total), and so on. How many Red and Black balls will there be on the nth draw? Will you still draw only finitely many red balls? Explain your answer. [4 marks]

amaranthwalrus338

1. A sample size of n=15 is a simple random sample selected from a normally distributed population. Using Table C, find the critical value t* corresponding to a 95% confidence level in the following scenarios:

a.............to construct a confidence interval

b..............one-sided hypothesis test

c..............two-sided hypothesis test

STATS 250 Lecture Notes - Lecture 8: Sampling Distribution, Confidence Interval, Normal Distribution

STATS 250 Full Course Notes

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