Question

Engineers concerned about a tower's stability have done extensive studies of its increasing tilt. Measurements of the lean of the tower over time provide much useful information. The following table gives measurements for the years 1975 to 1987. The variable "lean" represents the difference between where a point on the tower would be if the tower were straight and where it actually is. The data are coded as tenths of a millimeter in excess of 2.9 meters, so that the 1975 lean, which was 2.9642 meters, appears in the table as 642. Only the last two digits of the year were entered into the computer. Year 75 76 77 78 79 80 81 82 83 84 85 86 87 Lean 642 644 656 668 673 688 697 699 713 718 726 743 757 (a) Plot the data. Consider whether or not the trend in lean over time appears to be linear. (Do this on paper. Your instructor may ask you to turn in this graph.) (b) What is the equation of the least-squares line? (Round your answers to three decimal places.) y = -60.434 Incorrect: Your answer is incorrect. + 9.368 Incorrect: Your answer is incorrect. x What percent of the variation in lean is explained by this line? (Round your answer to one decimal place.) 99.7 Incorrect: Your answer is incorrect. % (c) Give a 99% confidence interval for the average rate of change (tenths of a millimeter per year) of the lean. (Round your answers to two decimal places.)

Answer 1

Interpretation:

The scatter plot of the variables Year (X) and the Lean (Y) depicts the strong positive linear relationship. Since, the direction is upwards. As the variable Year (X) increases, the variable Lean (Y) also increases in the same direction.

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