31 Match these Weibull data plotting patterns with their probable causes: - Data plots in two different sloped straight line segments - Data plots in a curved line, with the concave side facing upward - The data plots in a curved line, with the concave side facing downward. A. The population in test had some operating time before the test started. B. The population in test underwent some failure free time at the beginning of the test. C. Two different populations in test with different failure characteristics, or the strength of the test changed partway through the test