Why are most planets in our galaxy Jovian sized?

That's because bigger ones are easier to find. Majority of planetary bodies are most likely made of rock and ice, it's just that they're difficult to detect due to their smaller size.

Keep in mind that our mapping of the galaxy is still very incomplete.

What you are experiencing is just the result of observation bias.

The jovian sized planets are the easiest to detect. The planet detecting techniques just can't detect smaller planets in most circumstances.

For example, a particular planetary system might have 2 jovian-sized planets and 7 smaller planets. Our current technology can only see the 2 jovian-sized planets.

The newer observation satellite just launched (Gaia) will see better.

Well, we don't know for a fact that *most* are that big.... those are the one's we've *found* so far - and, we've found bigger planets because they're easier to find. As for only having 1 or 2 planets, we don't know that either (heck, we didn't know *our* solar system had Pluto sized worlds beyond the orbit of Pluto until 10 years ago...)

The planets we've found are only those that are massive enough to make their parent star wobble enough so that we can see them, or those that make transits across the star's face, so we can detect the dimming light; if a planet isn't massive enough to make a noticeable wobble, and not making the star's light dim, then we probably are unaware of it's presence.

It's more a matter of what planets we can spot using analysis techniques and interpretation of observations. A planet the size of the Earth (or Venus or Mars) is extremely small at distances of more than 4 light years. And massive planets (even if they are gas giants) have a larger effect (barely measurable) than the small planets, when the distances are measured in multiple parsecs.

If an elephant and an ant are standing next to each other, what is easier to see from a hundred feet away?

It isn't that Jovian planets are more numerous, but that they are much easier to find.

It's a "selection effect". It's easier to find big planets than small planets. It's easier to find planets near their stars than far from their stars. Therefore, most of the planets we know of are big and close to their stars.

Careful there.

Big Planets are a lot easier to find than smaller ones.

There are quite likely a lot more smaller ones out there than we can see.

The app's only showing the planets we know about - the bigger ones are the easiest to find. It's very likely there are many more, smaller, planets that we haven't discovered.

They probably aren't. What we have at present is a biased sample. It's much easier to detect large planets than small planets, so it appears that there are more large planets than small. In reality, small planets are probably much more common, as they are in our own system (when you include asteroids).

Bigger planets are easier for us to find at this time, so we find more large planets than small ones.

You are confusing what we have evidence of with what exists. As said, the smaller the planet, the harder it is to detect. One estimate is that there is at least one rocky planet (~terrestrial sized, 0.5 - 15 Earth masses) on average for each star (not saying each star has one, saying on average there are at least as many of each). (Estimate based on how many have been detected and how easy (difficult) they are to detect, published in Science mag. this summer)