A random sample of 10 university students was surveyed to determine the amount of time spent weekly at the library. The times are: 13 14 5 6 8 10 7 12 15 3
If the times are normally distributed with a standard deviation of 5.2 hours, with 90% confidence estimate the mean weekly time at the library by all university students. LCL= 8.445 hours
a. UCL = 10.155 hours LCL= 6.595 hours .
b. UCL = 12.005 hours LCL= 7.193 hours
c. UCL = 11.407 hours LCL= 0.747 hours O
d. UCL = 17.853 hours