Find a 90% prediction interval for the number of rooms hat would be cleaned when seven crews are used

Case Crews Rooms StdDev 1 16 51 12.00046 2 10 37 7.927123 3 12 37 7.28991 4 16 46 12.00046 5 16 45 12.00046 6 4 11 4.966555 7 2 6 3 8 4 19 4.966555 9 6 29 4.690416 10 2 14 3 11 12 47 7.28991 12 8 37 6.642665 13 16 60 12.00046 14 2 6 3 15 2 11 3 16 2 10 3 17 6 19 4.690416 18 10 33 7.927123 19 16 46 12.00046 20 16 69 12.00046 21 10 41 7.927123 22 6 19 4.690416 23 2 6 3 24 6 27 4.690416 25 10 35 7.927123 26 12 55 7.28991 27 4 15 4.966555 28 4 18 4.966555 29 16 72 12.00046 30 8 22 6.642665 31 10 55 7.927123 32 16 65 12.00046 33 6 26 4.690416 34 10 52 7.927123 35 12 55 7.28991 36 8 33 6.642665 37 10 38 7.927123 38 8 23 6.642665 39 8 38 6.642665 40 2 10 3 41 16 65 12.00046 42 8 31 6.642665 43 8 33 6.642665 44 12 47 7.28991 45 10 42 7.927123 46 16 78 12.00046 47 2 6 3 48 2 6 3 49 8 40 6.642665 50 12 39 7.28991 51 4 9 4.966555 52 4 22 4.966555 53 12 41 7.28991