## 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...

## 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...

## The definition of probability

The first task is to define precisely what is meant by probability. This is not as easy as one might imagine and there are a number of different schools of thought on the subject. Consider the following questions What is the probability of 'heads' occurring on the toss of a coin What is the probability of a driver having an accident in a year of driving What is the probability of a country such as Peru defaulting on its international loan repayments as Mexico did in the 1980s We shall use these...