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Normal Distribution and Linear Regression

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Question 1

During 2002 the number of beds required per day at St Hallam's hospital was normally distributed with a mean of 1800 and a standard deviation of 190. During the first 50 days of 2003 the average daily requirement for beds was 1830. A senior hospital manager claims that this gives evidence that the requirements for beds has changed since 2001. Do you agree?

Question 2

The following data were obtained in an experiment to estimate a possible relation between the number of showings in one week of a TV commercial in typical sales territories and the sales (in thousands of units) in that territory of the advertised article.

Territory 1 2 3 4 5 6 7 8 9 10
Showings 3 1 4 0 2 4 0 3 1 2
Sales 2.6 1.2 3 1 2 3.6 0.5 3.2 1.8 2.5

(i) Show that the data is significantly correlated.
(ii) Construct a scatter pot of the data.
(iii) Obtain a linear regression model for sales against number of showings per week.
(iv) What will be the estimated sales if there are 7 showings in a week? And for 20 showings?


Solution Summary

Problems involving linear regression and normal distribution are solved. The solution is detailed, well presented and includes a graph.