Modelling - A smooth, gradual descent/rise? Let me go straight to the issue at hand.

In my image below, you can notice several selected vertices.

Is there a way for me to make selected vertices rise, or descent, in a smooth, gradual manner automatically, or do I have to select each one of them separately and move them up or down by hand?

Any help in achieving my objective is highly regarded.



EDIT: Hi @Lee and @Robin Betts -

Thanks for the quick answers to my issue.
I tried both of the suggested methods but I failed to achieve what I was looking for. I may have missed something when trying them as I'm still new to Blender.

What I instead did is, go into Ortho - Right view, add and rotate a place as reference and move the vertecies until I get a smooth rise/descent.
(I deleted the plane afterwards so it's not in my screenshot but you can see the end result. Not the fastest way to work but ended up doing what I wanted anyway.)


EDIT Number 3: Man, what a pain this website format is.
Yes, actually! What you want for this task is proportional editing! If you'll look in the image below, you can access it via that icon, or by pressing 'O'. You have several falloffs to choose from, and you can choose if it should be affected by connected vertices, or anything under the circle (it makes a wide circle like when you use the brush select, and scrolling with the mousewheel adjusts the area of influence).