A sample of 150 brand A light bulbs showed a mean lifetime of 1392 hours and a standard deviation of 120 hours. A sample of 100 brand B light bulbs showed a mean lifetime of 1232 hours and a standard deviation of 80 hours. Which of the following is the 95% confidence interval for the difference of the mean lifetimes of the populations of brands A and B? a. (144.2,  175.8) b. (139.2,  180.8) c. (135.2,  184.8) d. (147.4,  172.6) e. (127.4,  192.6)

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Estimation

A new framework of data analysis where the new statistical methods are used for interpreting the results and analyzing the data is known as estimation in statistics.