Final answer:
The store manager at Big Lots is exhibiting convenience sampling bias by surveying only morning shoppers, which is not representative of all shoppers. This can result in skewed findings that do not accurately reflect the entire customer base's views on new store hours.
Step-by-step explanation:
The effect or bias mentioned in the scenario about the store manager at Big Lots randomly surveying 25 morning shoppers to determine the sentiments of all shoppers regarding new store hours involves the concept of sampling in statistics. This scenario likely points to a potential sampling bias called convenience sampling. By only surveying morning shoppers, the manager may not be getting a representative sample of all shoppers' opinions because it excludes those who shop at different times of day.
Convenience sampling often leads to biases because the sample may not accurately reflect the entire population's characteristics and thus may not yield generalizable results. To reduce sampling bias, a more robust sampling method, such as random sampling of shoppers throughout the entire day, would be advisable.