Apple iPhone Field Test- How good is this number?

This is my first time doing this and I'm a little confused because there usually isn't good signal where I live, so I want to hear another opinion of this because what I've researched doesn't make sense to me.

The numbers I have is between -114 and -118. Are the numbers fair or bad? Also between what numbers is the signal good or bad?

Anything above -80 is good, and would be considered full bars
Anything below -110 is bad, and would be considered few bars

Your numbers are considered poor (bad). To improve your reception, you'll need a signal extender, which includes a roof mounted antenna, wire and a transmitter connected inside your home, office, car, etc. These are not cheap, often costing over $500 for your home, and another one for each vehicle. I would recommend seeking a different carrier, which these sites may help you with: https://www.whistleout.com/CellPhones/iPhone-Everything-you-need-to-switch-carriers
https://www.howtogeek.com/271333/can-i-bring-my-iphone-to-another-carrier/

The problem is your carrier, not your phone. You live in an area where your current service provider doesn't provide full service to. As a result, you end up with poor reception, many dropped or missed calls, and similar problems. Any device you own will have that problem with that carrier, so changing devices will not help. Changing carriers or boosting their signal are your only options, short of opting not to use cellular services.
Any signal readings you take are only valid for the phone's individual carrier.
To get readings from other carriers, you'll need phones from each carrier.

Decibel signal strengths will generally be double or triple digits, and it will be negative. Some phones don't show a negative sign so if your phone shows just a number such as 90, the signal strength is really -90. The closer the number is to zero, the better the reception, so -80 is a stronger signal than -90. The unit of measurement is the decibel (dB), which is a measure of the power of a signal. Similar to the volume of a stereo, the numerical value is really telling you exactly how "loudly" your phone is receiving the signal from your provider's cellular network.

The decibel scale is not linear - an increase of 3 dB corresponds a signal that is twice as strong while a 10 dB increase corresponds to a 10 times increase in signal strength. So an RSSI value of -60 is actually ten times stronger than an RSSI of -70, for example.

For example, a signal number of -105 is considerably worse than a signal of -70. You'll generally find that anything approaching -105 or lower is fairly bad reception, while anything above -80 is usually good, and if you tap the number signal it's usually shown as full bars. The full range of the signal numbers extends from -40 to -120, with -130 being a nearly impossible number to see because it means no reception, and -40 would be about the strength you'd get being right alongside a cell tower. Technically, the number goes all the way to -140, but you will almost never see that because it basically means there's no signal to speak of, and most users will see -120 or -130 before it switches over to the "No Service" indicator instead.