Recent Question/Assignment

Complete the following questions using Microsoft Excel. Must be set out in Excel to show how answers were calculated.
Chap 16 Exercise 16.60 (The Normal Distribution)
The mean amount of pasta eaten by Italians each year is 26kg. If the amount follows a normal distribution with a standard deviation of 5 kg, in a random sample of 300 Italians, how many ( to the nearest whole number) would you expect to eat each year.
(a) Less than 30kg?
(b) More than 20kg?
(c) Between 20kg and 30kg?
Chap 17 Exercise 17.41 (Correlation)
The medium prices of houses sold during the year ending June 2008 for 12 areas in Sydney, along with their postcodes, are shown in the following table
Suburb Postcode (x) Median price ($’000) (y)
Hazelbrook 2779 302
Penrith 2750 305
Greystanes 2145 404
Kellyville 2155 579
Croydon 2132 752
Cherrybrook 2126 890
Balmain 2041 993
Lane Cove 2066 1040
Birchgrove 2041 1115
Pymble 2073 1200
Queenscliff 2096 1375
Church Point 2105 1425
(a) Using a scale between 2000 and 2800 for postcode on the horizontal axis, and a scale between 300 and 1500 for median price ($’000) on the vertical axis, draw a scatter diagram of the data.
(b) For these data:
S xx = 756 389 Syy= 1 733 714 Sxy= -822 255
Calculate the value of the correlation coefficient r
(c ) Test the value of r found in (b) for significance. What conclusions can you draw?
Chap 18 Exercise 18.31 (Regression Analysis)
The exchange rate between the Australian dollar (A$) and the US dollar (US$) on the 2nd of January is shown in the following table for each year between 2003 and 2012. The data shows how many cents US that A$ would purchase.
Year US Cents
2003 56.2
2004 75.0
2005 78.1
2006 73.3
2007 78.8
2008 87.5
2009 70.3
2010 89.7
2011 102.3
2012 97.9
(a) Plot the data on a scatter diagram and joint the points (place the year on horizontal axis) Do you see any linear trend? If not, What trend do you notice? Are there any outliers?
(b) Find the least squares regression line of US cents on year where the years are labelled as 1,2,3,4,…,10.
(c) Draw the line found in (b) on the scatter diagram in (a). Do you think it’s a good fit?