3- A researcher thinks that life time of light bulb has a normal distribution with mean of 3000 hours and variance of 50 hours. In order to construct 80 % confidence interval for the mean life time of...

Extracted text: 3- A researcher thinks that life time of light bulb has a normal distribution with mean of 3000 hours and variance of 50 hours. In order to construct 80 % confidence interval for the mean life time of light bulb randomly selected 16 sample light bulbs mean value is 2850 hours and sample variance is 25 hours. Find the confidence interval. (use 2 decimal point) a) None of them correct b) 2841.99 , 2858.01 2850.40 , 2849.60 2833.98 , 2866.03 2847.73, 2852.27