5 The digits of the number 1223678 can be rearranged to give many different 7 -digit numbers. Find how many different 7-digit numbers can be made if
- there are no restrictions on the order of the digits,
- the digits 1,3,7 (in any order) are next to each other,
- these 7 -digit numbers are even.
- In a normal distribution with mean \(\mu\) and standard deviation \(\sigma , \mathrm { P } ( X > 3.6 ) = 0.5\) and \(\mathrm { P } ( X > 2.8 ) = 0.6554\). Write down the value of \(\mu\), and calculate the value of \(\sigma\).
- If four observations are taken at random from this distribution, find the probability that at least two observations are greater than 2.8.