Review_Exam2

Review_Exam2 - Will a 90 confidence interval be narrower or...

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Exam 2 Review Data from a random sample of n = 50 Ames’ houses were collected in the year 2000. Two variables were used in the study: selling price (in dollars), and square footage (in square feet). 50000 100000 150000 200000 250000 300000 350000 Selling price 500 1000 1500 2000 2500 3000 Sqr footage Selling price Sqr footage Correlation Mean 138595 Mean 1441 0.8345 Std Dev 54517 Std Dev 490 N 50 N 50 Calculate the slope of the least squares line relating selling price to square feet: Calculate the intercept of this least squares line: Give the equation for the least squares line: Interpret the slope in the context of this data: Predict the expected selling price for a house with 2000 square feet: What is the form of the relationship between square footage and selling price assumed to be?
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Exam 2 Review Assume the selling price for population of all Ames homes has the N(μ ,54517) distribution. Calculate a 95% confidence interval for the mean selling price of all Ames homes from this sample of 50 homes:
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Unformatted text preview: Will a 90% confidence interval be narrower or wider than the 95% confidence interval? Calculate it: What is the margin of error for the 90% confidence interval? What about the 95% interval? If I collected another random sample of 50 Ames homes from this population what might change about the 95% interval? What would remain the same? If the population distribution is not Normal , can I still use these confidence interval formulas? Why? Calculate a 95% confidence interval for the mean square footage of all Ames homes ( : What is meant by the phrase “95% confident” in the interpretation of the above interval? Why is this interval narrower than the 95% confidence interval for the mean selling price? If I wanted the width of the 95% confidence interval for the mean square footage to be 100, how many homes would I need to include in the sample?...
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Review_Exam2 - Will a 90 confidence interval be narrower or...

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