Select all the correct answers. Select all the studies in which the results may have been skewed by bias.

a study with a significantly larger than expected standard deviation about the sample mean
a study on the heights of a group of fourth graders, where 90% of the data fell below the population mean
a study on the average life span of a type of plant, where 50% of the data fell above the population mean
a study of the average annual rainfall, with 28% of the data having a z-score greater than 1
a study on employees’ commute time, with 90% of the data falling within 1 standard deviation of the population mean
a study of the popularity of a particular music genre, with a small standard deviation about the mean