Let X = Hourly Median Power (In Decibels) of Received $\mu = 3.5 \text { and } \sigma = 1.2 \text {, }$

Essay

Let X = hourly median power (in decibels) of received radio signals transmitted between two cities. It is believed that the lognormal distribution provides a reasonable probability model for X. If the parameter values are $\mu = 3.5 \text { and } \sigma = 1.2 \text {, }$ calculate the following:
a. The mean value and standard deviation of received power
b. The probability that received power is between 50 and 250 dB
c. The probability that X is less than its mean value. Why is this probability not .5?