system has four independent and identical units in parallel. Each unit’s failure rate is 0.0005 failures/h. Calculate the system reliability, if at least two units must operate normally for the system success during a 100-h mission

A new town was incorporated in 1960. The size of the town's population was recorded every 5 years after 1960. Using the variables x, for number of years since 1960, and y, for the size of the population, three models were created to predict the population from the number of years since 1960.

in 2017, the residents of eugene were producing greenhouse gas emissions at an average rate of 16 tons of co2 per resident per year, and that the amount was decreasing at an instantaneous rate of .22 tons per year. however the population of euegene was 170,000 and growing at a rate of 2,000 people per year. at what instantaneous rate was the total greenhouse gas emissions in eugene growing in 2017 ?

Lise Meitner bombarded 300 uranium atoms with a stream of neutrons for 10 seconds each.  She recorded the energy released when the uranium atom was split.  What is the sample of this study?