STATISTICS Help!

[haloman]

Question 1. (Descriptive Statistics)

Investment Returns:   These data are the annual returns on shareholders’ funds of 95 of Australian’s top 100 companies for the years 1990 and 1998.

(i)   Produce a histogram of the 1990 returns.
 
(ii)   Produce a histogram of the 1998 returns.
    
(iii)   Find the mean, median, range and standard deviation for the 1990 returns

(iv)   Repeat part (iii) for the 1998 returns

(v)   Which was the better year for investors?



Question 2.   (Statistical Inferences: Single Population)

Feasibility Study: Companies that sell groceries over the Internet are called e-grocers. Customers enter their orders, pay by credit card and receive delivery by truck. To determine whether an e-grocery would be profitable in one large city, a potential e-grocer offered the service and recorded the size of the order for a random sample of customers. The data are stored in the data file.

(i)   Estimate with 95% confidence the average order in the city.

(ii)   Financial analysis indicates that to be profitable the average order would have to exceed $90. Can we infer from the data that an e-grocery will be profitable in the city? Test using a = 0.05


Question 3.    (Statistical Inferences: Two Populations)

To sell or not to sell: The fluctuations in the stock market induce some investors to sell and move their money into more stable investments. To determine the degree to which recent fluctuation affected ownership, a random sample of 160 people who confirmed that they owned some shares were surveyed. The values of the holdings were recorded at the end of last year and at the end of the year before. Can we infer that the average value of the shareholdings has decreased? Use a = 0.05.



 
Question 4.   (Simple Linear Regression)
 
Insurance Premium: A health economist is investigating whether there is any relationship between people’s age and their medical expenses. He gathered data concerning the age and average daily medical expenses of a random sample of 300 Australians during the previous 12-month period. The data are stored in the data file.

(i)   Determine the equation of the regression line to predict the daily medical expense by a person’s age.
(ii)   Interpret the coefficients.
(iii)   Find the coefficient of determination. What does this statistic tell you abut the regression line?
(iv)   Can we conclude at a 5% significance level that higher ages result in higher daily medical expenses?
(v)   Predict with 95% confidence the daily medical expense of a 60-year-old Australian.



Can anyone provide me answers with working out for these four questions, I am having trouble. THANKYOU very much. THE DATA FILE ON WORD IS ATTACHED.

[haloman]

ANYONE KEEN TO HELP?

[ninwa]

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