i'm stuck on this step and am having trouble figureing out function to put into the individual cell that will give me my correct results

13 Next, you will determine if there is a significant difference between the average amount spent at the spa and the average amount spent at the spa for non-spa (Null) members. To gather this information, you will need to create a formula based on two sets of criteria. In cell C4, enter a function to calculate the average if the guest stayed at least 4 nights and is a non-spa (Null) customer. H A D Spa Sales Analysis Number of Spa Customers Average Spa Sales Spa Sales 10 $89099 $2,659.50 2 $4,543.12 2 3 Guest Criteria 4 Null Whole Days Spent 1 2 4 2 4 Wedding Party Name 7 Arroyo B Proctor 9 Minor 10 Pearce 11 Shes Galvan 13 Crowe 14 Meeks 15 Kendrick 16 Mayfield 17 Kendall 18 Archer 19 Holley 20 Boucher 21 childs 22 Rankin 23 Lotano 24 Odell 25 Bland 2 Rouse 27 Hans 2 3 4 3 4 4 Value of Returned Amount Spent at Merchandise Spa $ 37.34 1,215 69 $ 41.125 72060 $ 12.70 $ 45578 $ 13.97S 1,309.51 5 18.59 1,345 57 S 11.095 1,046,69 S 36.64 $ 1125.53 S 47.703 1,068.90 $ 10.24 604.95 $ 7888 299,60 $ 21.78 353.74 $ 37.51s 923.56 S 34 36 1.285.26 $ 5.79$ 1157.07 $ 2.47S 206.77 $ 12 665 781.30 $ 49.745 1070.70 $ 18.66 $ 867.45 5 17 B6 S 267 16 $ 24985 1,33038 $ 23.125 899.22 5 7.23 5 1,479.14 $ 1115 953 20 $ 0,465 556.17 $ 19.03 644 50 $ 3155 606,30 40.745 955 27 $ 16.60S 750.12 31.055 870,85 5 2591 1,146,79 s 30665 307.42 1 4 2 4 Spa Member 1 1 1 Null 1 1 1 1 Null Null Null -1 Null 1 1 Null Null Null 1 1 Null Null 1 Null Null 1 Noll 1 1 1 Null 2 1 4 1 2 23 Oconnell 30 Doutherty 31 Andersen 5 1 33 Coman 34 Elder 35 Shirley 1 1 2 3 4 31 Teli AD Wedding Summary SpaServices Wedding Financing Commission Sale Type here to search