The difference between the words “tycker”, “tänker” and “tror” might be confusing when you are learning Swedish, since all three of them translates to “think”. I will try my best to sort things out for you in this matter.
We can start with”tycker”. It can be translated to “think” meaning consider, be of the opinion or feel. So when we use “tycker” we are dealing with a (personal) evaluation of something, not a fact. I think something and you might think something else, and we can’t say that one of us is right and the other one is wrong. I should give you a couple of examples.
1. Jag tycker att Maria borde gå hem. (I think that Maria should go home.)
2. Jag tyckte att filmen var bra. (I thought that ít was a good movie.)
In example number 1 i use “tycker” because it is my personal opinion that Maria should go home. Maria herself might not want to leave. In example number 2 I also have to use “tycker” since I am saying that the movie was good (bra), it is my personal opinion. Maybe you think that the movie was crap. The same thing goes for words like “dålig”, “ful”, “snygg” and “tråkig”. They go together with “tycker”.
“Tror” on the other hand translates to “think” in the sense “believe” or “assume”. It is also a way to express the meaning of English “likely” or “probably”. Therefore, if you are a student or a researcher and have got some interesting results, you should talk about what you “tror” and not what you “tycker”. A couple of examples with “tror”:
1. Jag tror att Maria ska gå hem nu. (I am assuming that Maria is going home now.)
2. Jag tror att filmen är regisserad av Lasse Hallström. (I assume/think that the movie is directed by Lasse Hallström.)
3. Forskarna tror att de har hittat ett bot mot sjukdomen. (The scientists think that they probably have found a cure for the disease./ The scientists have probably found a cure for the disease.)
Comparing example number 1 with “tycker” we can now see that when using “tror” I don’t express any personal feelings about Maria and her leaving. The same thing goes for example 2, I don’t express anything about the quality of the movie, only who I assume directed it.
Have fun speaking Swedish! And dont be shy asking me questions 
Sara The Swedish Teacher
