One situation where a data analyst might face a challenge validating data is when working with manually entered survey responses. For example, if the analyst is reviewing employee satisfaction data and finds an age listed as 250 or a salary that is missing a decimal point, those are clear signs of invalid entries. To confirm if the dataset is valid, I would load the data into RStudio and use basic descriptive statistics like mean, maximum, minimum, and standard deviation. I would also review percentiles to see if any values fall outside of what I expected. From there, I would check for formatting errors, missing values, or duplicate entries