S4n to under 334 The Olive Garden Italian Restaurant records

S4n to under 3.34 The Olive Garden Italian Restaurant records the amount of time customers wait for a table on Saturday evenings

Solution

Variance = 138500 / 100 - (33.8)^2

Stdev = sqrt(Variance)

Hope this helps.

Class	Freq	Mid.Pt	product	Mid.pt^2	product
0-10	6	5	30	25	150
10-20	22	15	330	225	4950
20-30	10	25	250	625	6250
30-40	18	35	630	1225	22050
40-50	28	45	1260	2025	56700
50-60	16	55	880	3025	48400
Total	100		3380	7150	138500
Mean	33.8
Variance	242.56
Stdev	15.57434