Q. Describe about Price level and time?

We are hardly interested in the value of price level at a certain point in time. What we are interested in is percentage change in the price level between two points in time.

We evaluate the percentage change by first creating a basket of services andgoods. At regular intervals (generally once a month on the first day of the month) we measure all prices of the contents of the basket (characteristically as an average of the market) and evaluate the price level. In this way, we would end up with a time series of price levels - one value for each month.

Using this time series we can study how price level progresses over time. If all prices rose by 2% during one month, price level would rise by exactly 2%. If one of the prices rose by 2% whereas the other prices remained unchanged, price level would rise, though by much less than 2%. Exactly how much it would rise will depend on the weight of changed price.

Imagine that we have created a particular basket of services and goods. We evaluate the price level at 4 different points in time during 2008 without changing content of basket (weights are unchanged). Assume that we find the below time series for the price level: