## Info

(a) Draw an XY plot of the data and comment. (b) From the chart, would you expect the line of best fit to slope up or down In theory, which way should it slope (c) What would you expect the correlation coefficient to be, approximately (d) Calculate the correlation coefficient between margarine consumption and its price. (e) Is the coefficient significantly different from zero What is the implication of the result (The following totals will reduce the burden of calculation YY 67.52 YX 2101.70...

## Probability theory and statistical inference

In October 1985 Mrs Evelyn Adams of New Jersey, USA, won 3.9 million in the State lottery at odds of 1 in 3 200 000. In February 1986 she again won, though this time only 1.4 million at odds of 1 in 5 200 000. The odds against both these wins were calculated at about 1 in 17 300 billion. Mrs Adams is quoted as saying 'They say good things come in threes, so . . .'. The above story illustrates the principles of probability at work. The same principles underlie the theory of statistical...

## Is A 95 Confidence Interval Twice As Wide As A 47.5 Confidence Interval

Some of the more challenging problems are indicated by highlighting the problem number in colour. a Why is an interval estimate better than a point estimate b What factors determine the width of a confidence interval Is the 95 confidence interval a twice as wide, b more than twice as wide, c less than twice as wide, as the 47.5 interval Explain your reasoning. Explain the difference between an estimate and an estimator. Is it true that a good estimator always leads to a good estimate Explain...