View Single Post
      02-28-2013, 11:46 PM   #38
Artmasterx's Avatar

Drives: 2007 BMW 335i
Join Date: Jun 2008
Location: MA

iTrader: (0)

Garage List
2006 Volvo V70R  [5.00]
2007 BMW 335i  [5.00]
Everyone, I have compiled initial statistics based on 106 responses so far.

This gives the failure probability and the +/- 95% confidence intervals for that failure rate. Obviously, we need more data points to get more confidence, especially at higher mileages.

Everyone help out by voting!

Also, there will likely be a skew towards more failures given that many people with healthy water pumps may not check out the thread.

The plot gives the failure rate as a function of mileage. In the x-axis I list the total responses for each mileage bin. For those of you interested in the calculation details:

Total response in each bin = n_i
Failure probability for each bin (p_i): p_i = #dead_i / n_i
95% Confidence Interval (CI): CI_i = +/- 1.96*[ p_i*(1-p_i) / n_i ]^0.5

Current: 2007 335i sedan
Alpine White | Sports | Premium | Cold | Comfort Access

FORMERLY: 128i coupe
Alpine White | Sports Package | Black Leather