document.write( "Question 782815: Question 1 (3 marks = 0.5 + 0.5 + 1 + 1)
\n" ); document.write( "A busy landscaping supplies company sells wood chips for garden mulch. The mulch is sold by the cubic metre and delivered to households in a small truck. Each truckload is expected to be 4 cubic metres. The company decides to conduct an audit of actual load volumes by measuring a sample of loads for a two-week period. The data file Mulch.xls contains the volume (in cubic metres) from a sample of 368 truckloads of cypress pine wood chips and 330 truckloads of cedar wood chips.
\n" ); document.write( "a. For the cypress pine wood chips, construct a 95% confidence interval estimate of the mean volume.
\n" ); document.write( "b. For the cedar wood chips, construct a 95% confidence interval estimate of the mean volume.
\n" ); document.write( "c. The company is interested to know whether there is a linear relationship between the delivery volumes for the two types of wood chips. Calculate a correlation coefficient for the first 330 pairs of observations and test whether this relationship is significant at the 1% level. Make sure you state the hypotheses that you are testing.
\n" ); document.write( "d. Based on the results of (a) and (b), what conclusions can you reach concerning mean volume of the cypress pine wood chips and cedar wood chips?
\n" ); document.write( "Question 2 (4 marks = 0.5 + 0.5 + 0.5 + 0.5 + 0.5 + 0.5 + 1)
\n" ); document.write( "In a random sample of 25 observations from a normal population, we found that the sample mean = 140, and the sample standard deviation = 10. Using a level of significance of 0.05, test the hypothesis that the population mean is 150. You are required to:-
\n" ); document.write( "a. State the type of test that you are going to use.
\n" ); document.write( "b. State the hypotheses that you are going to test.
\n" ); document.write( "c. Calculate the standard error.
\n" ); document.write( "d. Calculate the t-statistic.
\n" ); document.write( "e. Calculate the p-value.
\n" ); document.write( "f. Draw your conclusion.
\n" ); document.write( "g. Determine the 95% confidence interval of the population mean and state whether it supports your conclusion given in f) above.
\n" ); document.write( "Question 3 (2 marks = 0.5 + 0.5 + 0.5 + 0.5)
\n" ); document.write( "The fill amount of soft drink bottles is normally distributed with a mean of 2.0 litres and a standard deviation of 0.05 litres. If you select a random sample of 25 bottles, what is the probability that the sample mean will be…
\n" ); document.write( "a. Between 1.99 and 2.0 litres?
\n" ); document.write( "b. Below 1.98 litres?
\n" ); document.write( "c. Above 2.01 litres?
\n" ); document.write( "d. The probability is 99% that the sample mean will contain at least how much soft drink?
\n" ); document.write( "Question 4 (7 marks = 2 + 2 + 2 + 1)
\n" ); document.write( "It is believed that a linear relationship exists between Salary (the dependent variable) and the employees experience measured in years (the independent variable) for Diploma graduates. Using the summary data from a sample of 10 employees:
\n" ); document.write( " experience = 93, = 975, salary = 1014, = 105104, = 9922
\n" ); document.write( "a. Provide the regression line equation for this sample. Interpret the coefficient and the intercept.
\n" ); document.write( "b. Calculate the standard error of estimate and describe what it tells you about the model fit.
\n" ); document.write( "c. Test to determine whether there is enough evidence to infer that a linear relationship exists between experience and salary at the 0.01 significance level. Make sure you state the hypotheses that you are testing.
\n" ); document.write( "d. Use your model to predict the expected salary where an employee has 15 years of experience or state why it is not possible to do so.
\n" ); document.write( "Question 5 (9 marks = 2 + 1 + 1 + 1 + 2 + 1 + 1)
\n" ); document.write( "A transport company wishes to predict the price of petrol based on international crude oil prices. They record average monthly petrol prices and crude oil prices over a 12 month period.
\n" ); document.write( "Month Petrol Price ($/litre) Crude Oil Price ($/barrel)
\n" ); document.write( "January 1.25 72
\n" ); document.write( "February 1.32 75
\n" ); document.write( "March 1.15 69
\n" ); document.write( "April 1.35 82
\n" ); document.write( "May 1.22 78
\n" ); document.write( "June 1.26 80
\n" ); document.write( "July 1.43 91
\n" ); document.write( "August 1.29 84
\n" ); document.write( "September 1.28 82
\n" ); document.write( "October 1.17 79
\n" ); document.write( "November 1.52 98
\n" ); document.write( "December 1.43 91
\n" ); document.write( "a. Plot a scatter diagram and, assuming a linear relationship, use the least-squares method to calculate the regression equation for this data. You will need to show your calculations for SSX, SSXY, and .
\n" ); document.write( "b. Interpret the meaning of the Y intercept, and the slope, in this problem.
\n" ); document.write( "c. Use the prediction equation developed in (a) to predict the petrol price if crude oil is $75 per barrel.
\n" ); document.write( "d. Calculate the coefficient of determination, r2, and interpret its meaning in this problem.
\n" ); document.write( "e. Perform a residual analysis on your results and determine whether the sample data meet the linear regression assumption of equal variance (homoscedasticity).
\n" ); document.write( "
\n" ); document.write( "f. At the 0.05 level of significance, is there evidence of a linear relationship between petrol and crude prices? Make sure that you state the hypotheses you are testing.
\n" ); document.write( "g. Construct a 95% confidence interval of the population slope.
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Algebra.Com's Answer #476531 by oscargut(2103)\"\" \"About 
You can put this solution on YOUR website!
You placed a lot of question in one post\r
\n" ); document.write( "\n" ); document.write( "I am available to help if you contact me at: mthman@gmail.com\r
\n" ); document.write( "\n" ); document.write( "Thanks
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