QUESTION 7 A random sample of 100 households was selected as part of a study on electricity usage, and the number of kilowatt-hours (KWh) used last quarter was recorded for each household in the sample. The average usage was found to be 359.102 KWh. The standard deviation of the usage was 81 KWh. Find the upper confidence limit of the 99% confidence interval for the mean usage in the last quarter. O a. 386 KWh O b. 380 KWh O C. 388 kWh O d. 382 kWh O e. 384 KWh