Shuffle questions Question 1 of 13 A manager at a high-end restaurant claims that people who order expensive wine tip better. He takes a sample of 20 receipts from the end of the evening where the table ordered a bottle of wine, and compares the price of the bottle of wine to the amount of tip that was left. He notices that the results tend to match his hypothesis, with the exception of two obvious outliers, which are so far removed from the rest of the data that he discards them and uses the remaining 18 receipts. The correlation coefficient generated with the remaining 18 receipts is r = 0.918, Based on this result, he concludes there is strong positive correlation between people who buy expensive wine and people who tip well. Identify three problems with this study that may have skewed his results. Self-selected sample, small sample size, and sample is not varied O Small sample size, unreliable results, and sample is not varied O Self-selected sample, correlation doesn't mean causation, and unreliable results Self-selected sample, small sample size, and unreliable results