An important product is cost sampled for significant components and over the years a product index is faithfully calculated. The following is the table of indexes.

1. Determine the values of parameters a and b of the linear regression equation using the least-squares method.
2. Find the 90% prediction interval for the year 10 value. Estimate the 95% confidence interval for the slope.
3. The product cost for year 9 is $17,500 per unit. Find the expected cost and the 90% upper and lower values of the cost for year 10.
4. Determine the coefficient of correlation, r . What can you say about the strength of the prediction of the cost range?

Year	Product Index, y
0	$95.1
1	$97.7
2	$98.4
3	$100.0
4	$101.1
5	$102.2
6	$103.5
7	$104.9
8	$106.6
9	$109.7