An electrical manufacturing firm producing molded case circuit breakers claims that their breakers will last, on average, 30 years with a variance of 12.5 years. If five of these breakers have a...

An electrical manufacturing firm producing molded case circuit breakers claims that their breakers will last, on average, 30 years with a variance of 12.5 years. If five of these breakers have a variance of 10.89 years, construct a 95% confidence interval for the variance and decide if the manufacturing firm's claim that a variance of 12.5 years is valid. Assume the population of the breaker lives to be approximately normally distributed.