assume that the weights of 18-year old males in a population follow a normal distribution with mean 65 kg and standard deviation 11 kg. a) find the probability that a randomly chosen male weighs more...

Let X be the random variable denotes the weight of 18-year-old males follows normal distribution.
Assume that the weights of 18-year-old males in a population follow a normal distribution with mean 65 kg and standard deviation 11 kg.
Hence, .
a)
The probability that a randomly chosen male weighs more than 70 kg is calculated as follows:
(Using Standard normal table)
Hence, the probability that a randomly chosen male weighs more than 70 kg is 0.3247.
b)
The interquartile range is difference between first and third quartile.
The first quartile is calculated as follows:
From standard normal table value of c is -0.675.
Hence,
The third quartile is calculated as follows:
From standard normal table...