Salina has an outstanding electricity bill of RM48.30 from the previous month. Her electricity bill for this month is RM45.15 and she pays RM150 for the bills of three months via online banking. How much money does Salina have to pay for the next month if the current charge of her electricity bill is RM46.80?

Arandom sample of 15 observations is used to estimate the population mean. the sample mean and the standard deviation are calculated as 172 and 63, respectively. assume that the population is normally distributed. a. with 99 confidence, what is the margin of error for the estimation of the population mean? b. construct the 99% confidence interval for the population mean. c. construct the 95% confidence interval for the population mean. d. construct the 83% confidence interval for the population mean. hint: you need to use excel function =t. inv.2t to find the value of t for the interval calculation.