# Wk3 Assignment Bus 308

Pages: 3 (802 words) Published: May 21, 2012
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Chapter 7: 7.11
Suppose that we will randomly select a sample of 64 measurements from a population having a mean equal to 20 and a standard deviation equal to 4. A. Describe the shape of the sampling distribution of the sample mean x. Do we need to make any assumptions about the shape of the population? Why or why not? -------------------------------------------------

This would be a normally distributed bell shaped curve. We do not need to make any assumptions because the sample size is at least 30. B. Find the mean and the standard deviation of the sampling distribution of the sample mean x. a. µx=µ +ox=σx=σn µ=20 464=48=.5= σ=.5

C. Calculate the probability that we will obtain a sample mean greater than 21; that is, calculate Px>21. Hint: Find the z value corresponding to 21 by using µx, and σx because we wish to calculate a probability about x. Then sketch the sampling distribution and the probability. a. Px>21 if µ=20) P(z>21-20.5=2 P(z>21)=P(z>)=.0228 A sample distribution normal curve with μx = 20 and σx = .5| | | | | | | | | |

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-1.5| .2 -1| | -.5| 0| .5| 1| .2| 1.5|

D. Calculate the probability that we will obtain a sample mean less than 19.385; that is, calculate Px<19.385. b. Px<19.385 if µ=20=Pz<19.385-20.5Pz<-1.23=.1093 -------------------------------------------------

Chapter 7: 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...