Week 3 Assignments

Week 3 Assignments
Debra Shaffer
BUS308
Travis Hayes
May 14, 2012

Week 3 Assignments
7.11; sound out that we go away randomly select a sample of 64 measurements from a population having a mean equal to 20 and a standard deflexion equal to .4
a.) Describe the term of the sample distribution of the sample mean xbar. Do we pauperisation to make any assumptions or so the shape of the population? why or why not?
Following the central intimidate theorem, the distribution of x bar is designly distributed showing a bell shape. No assumptions need to be made about the distribution of population. If there are a lot of measurements, the x bar will converge in distribution to normal from Central Limit Theorem. (Bowerman, 2012)
b.) Find the mean and the standard deviation of the sampling distribution of the sample mean x-.
Mean (x bar) = 1/n sum from 1 to n mean(x_i)
= 1/n * n * mean (x_1) because all x_i are identically and separately distributed.
= mean (x_1) = mean(x) = 20
sd(x-) = sd(x)/ sqrt(n) = 4/8 = 1/2
c.) Calculate the chance that we will obtain a sample mean great than 21; judge P(xbar>21).
z value = (21 - 20) * 2 = 2
P(Z > 2) = 0.02
sampling distribution is bell-shaped curve. the curve is centered at 20. you whole tone out the part that is greater than 21.





21
21
20
20


d.) Calculate the probability that we will obtain a sample mean less than 19.385, calculate P(x-- < 19.385).
z value (19.385 - 20)*2 = -1.23
P(Z < -1.23) = 0.11
7.30; On February 8, 2002 the Gallup Organization released the results of a poll concerning American attitudes toward the 19th Winter Olympic Games in Salt Lake City, Utah. The poll results were based on telephone interviews with a randomly selected national sample of 1,011 adults, 18 years and older, conducted February 4-6, 2002.
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