Answer:
18000/67 是 268.657
希望有帮助:)
Step-by-step explanation:
1 out of 4 I'm pretty sure
Answer:
(115.2642, 222.7358).
Step-by-step explanation:
Given data:
type A: n_1=60, xbar_1=1827, s_1=168
type B: n_2=180, xbar_2=1658, s_2=225
n_1 = sample size 1, n_2= sample size 2
xbar_1, xbar_2 are mean life of sample 1 and 2 respectively. Similarly, s_1 and s_2 are standard deviation of 1,2.
a=0.05, |Z(0.025)|=1.96 (from the standard normal table)
So 95% CI is
(xbar_1 -xbar_2) ± Z×√[s1^2/n1 + s2^2/n2]
=(1827-1658) ± 1.96×sqrt(168^2/60 + 225^2/180)
= (115.2642, 222.7358).
Answer:
Step-by-step explanation:
Data provided in the question
Number of bags of mulch = 7.5 bags
Number of square yards = 12
So by considering above information, we could find the number of bags for each square yard is
= 
= 
= 0.625
The 0.625 is equal to bag
Therefore, she need to use bag for each square yard
Basically we use the fraction so that each square yard for use of bag could be find out
