Best Buy claims that 68% of people that walk into one of their stores end up not purchasing an item. To test this, they randomly
sample 30 customers at one of their locations. Is there enough evidence to show that the proportion of people who walk into Best Buy and don't buy anything is different than 68%
As long as the individual's that have been selected as part of the study were actually selected randomly then yes. If there was no bias or other external factors affecting the probability of getting chosen then these individual's would clearly represent the entire population of Best Buy customers. Therefore, if the data gathered from these individuals results in being 68% of that population that does not buy anything then this would result in a valid claim by Best Buy.
