=+from moderate to heavy humidity. For each brand, a sample of four humidifiers was randomly assigned, one each, to the four humidity levels. The resulting annual power consumption (in kilowatt-hours) is given in the following table:

Humidity level Brand 1 2 3 4 1 685 792 838 875 2 722 806 893 953 3 733 802 880 941 4 811 888 952 1005 5 828 920 978 1023