a store manager is looking at past jewelry sales to determine what sizes of rings to keep in stock. the list…

a store manager is looking at past jewelry sales to determine what sizes of rings to keep in stock. the list shows the ring sizes purchased by the last ten jewelry customers. 9, 7, 6.5, 7.5, 7, 8, 5, 6, 7.5, 8 what is the variance of the data set? round to the nearest hundredths. 0.40 0.72 1.15 2.14

a store manager is looking at past jewelry sales to determine what sizes of rings to keep in stock. the list shows the ring sizes purchased by the last ten jewelry customers. 9, 7, 6.5, 7.5, 7, 8, 5, 6, 7.5, 8 what is the variance of the data set? round to the nearest hundredths. 0.40 0.72 1.15 2.14

Answer

Explanation:

Step1: Calculate the mean

The data set is (9,7,6.5,7.5,7,8,5,6,7.5,8). The sum of the data is (9 + 7+6.5 + 7.5+7+8+5+6+7.5+8=71.5). There are (n = 10) data - points. The mean (\bar{x}=\frac{71.5}{10}=7.15).

Step2: Calculate the squared - differences

((9 - 7.15)^2=(1.85)^2 = 3.4225), ((7 - 7.15)^2=(-0.15)^2 = 0.0225), ((6.5 - 7.15)^2=(-0.65)^2 = 0.4225), ((7.5 - 7.15)^2=(0.35)^2 = 0.1225), ((7 - 7.15)^2=(-0.15)^2 = 0.0225), ((8 - 7.15)^2=(0.85)^2 = 0.7225), ((5 - 7.15)^2=(-2.15)^2 = 4.6225), ((6 - 7.15)^2=(-1.15)^2 = 1.3225), ((7.5 - 7.15)^2=(0.35)^2 = 0.1225), ((8 - 7.15)^2=(0.85)^2 = 0.7225).

Step3: Calculate the sum of squared - differences

The sum (S=3.4225 + 0.0225+0.4225+0.1225+0.0225+0.7225+4.6225+1.3225+0.1225+0.7225 = 11.5).

Step4: Calculate the variance

The variance (s^{2}=\frac{S}{n}=\frac{11.5}{10}=1.15).

Answer:

1.15