what is the null hypothesis? what is the alternative hypothesis? what is the level of significance?

Saeko owns a yarn shop and want to expands her color selection. Before she expands her colors, she wants to find out if her customers prefer one brand over another brand. Specifically, she is interested in three different types of bison yarn. As an experiment, she randomly selected 21 different days and recorded the sales of each brand. At the .10 significance level, can she conclude that there is a difference in preference between the brands? Misa's Bison Yak-et-ty-Yaks Buffalo Yarns 799 776 799 784 640 931 807 822 794 675 856 920 795 616 731 Total 875 893 837 4,735.00 4,603.00 5,012.00