I am given this information about the incidence rate of stroke (per 1,000) for males for these age groups:
- 18-44: 6
- 45-54: 19
- 55-64: 35
- 65-74: 64
However, I need the incidence rates in these age groups: 20-29, 30-39, 40-49, 50-59, and 60-69. Is it possible to interpolate/estimate the rates for each individual age (20, 21, 22… 67, 68, and 69) based on the given information? I know how to use the trend formula in Excel, but that can only be used when the known x-values are numbers (not a range of numbers). Please let me know if there is a way I can get the information I need. Thank you.
Best Answer
The best you can do is to do a trend of the strokes/year density function using the midpoint of each range as $x$ and the total strokes for the range divided by the number of years as the density value; thus you would trend for $$ \begin{array}{cc} 31 & \frac{6}{27} = 0.22 \\ 49.5 & \frac{19}{10} = 1.9 \\ 59.5 & \frac{35}{10} = 3.5 \\ 69.5 & \frac{64}{10} = 6.4 \\ \end{array} $$ Then make a column of years and insert the trend formula in the column next to it. Now you can sum any particular 10 (or other number) of years based on the numbers in the trend column.