Question 1187761
Low negative correlation.
If the sample size were 1000, the correlation has increased likelihood of being statistically significant. That's one possibility. Another is that a there are too few wealthy people in a sample of 50 to mean much of anything. A third issue is that wealth isn't clear here. A fourth issue might be that with 1000, there are more wealthy people so that the correlation may no longer be negative. 
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Non-random sample: taken from center city, suburbs, the state, people chosen in the sample who will not reply, give a wrong value. For a sample to be random, every person in the population must have a non-zero probability of being chosen. The likelihood may be very close to zero, but it is not zero.  If a whole swath of the country is not considered, for example, the sample is not random. Those are some of the reasons. Sampling technique (SRS, stratified, systematic, cluster) also needs to be appropriate.