Question

if I have two lists:

A = {132.65, 327.86, 0.08, 1059.22, 5.29, 0.0, 454.04, 0.0, 193.67, 940.54}

B = {28.31, 0.0, 0.0, 6.71, 2336.61, 0.0, 90.17, 6.4, 244.29, 87.38}

I want to test if the variance of B is greater than A, how should I test it?

what is my Null and Alternative Hypothesis? what test should I run? and what is the result? do I reject my null and why?

Answer 1

Null Hypothesis:

Ho:

Ha:

alpha=0.05

Rcode:

A <- c(132.65, 327.86, 0.08, 1059.22, 5.29, 0.0, 454.04, 0.0, 193.67, 940.54)

B <- c(28.31, 0.0, 0.0, 6.71, 2336.61, 0.0, 90.17, 6.4, 244.29, 87.38)

var.test(B,A,alternative = "greater")

Output:

F test to compare two variances

data: B and A
F = 3.3798, num df = 9, denom df = 9, p-value = 0.04204
alternative hypothesis: true ratio of variances is greater than 1
95 percent confidence interval:
1.063201 Inf
sample estimates:
ratio of variances
3.379801

Intrepretation:

F test statisitc,F=3.3798

p value=0.04204

alpha=0.05

pvalues les than alpha

Reject Ho as p<alpha

Accept Ho

Conclusion:

There is suffcient statistical evdience at 5% level of significance to conlcude that variance of B is greater than variance of A