Question

Using the data from the previous question on LDL cholesterol, you decide to test if the variance in LDL cholesterol of patients admitted to the hospital with a heart attack is the same as that of those who have not (the control). You use the R function var.test and obtain the following output.

   F test to compare two variances

data: ldl.ha and ldl.cont

F = 7.683, num df = 9, denom df = 15,
   p-value = 0.0006501

alternative hypothesis: true ratio of
variances is not equal to 1

95 percent confidence interval:

2.460444 28.960945

sample estimates:

ratio of variances

          7.683258

What null and alternative hypotheses were tested?

	A.	H0: s12 = s22 H1: s12 > s22
	B.	H0: s2 = 1 H1: s2 > 1
	C.	H0: s2 = 1 H1: s2 ≠ 1
	D.	H0: s12 = s22 H1: s12 ≠ s22

Using the data from the previous question on LDL cholesterol, you decide to test if the variance in LDL cholesterol of patients admitted to the hospital with a heart attack is the same as that of those who have not (the control). You use the R function var.test and obtain the following output.

   F test to compare two variances

data: ldl.ha and ldl.cont

F = 7.683, num df = 9, denom df = 15,
   p-value = 0.0006501

alternative hypothesis: true ratio of
variances is not equal to 1

95 percent confidence interval:

2.460444 28.960945

sample estimates:

ratio of variances

7.683258

How many observations from each population did you have?

	A.	10 and 16
	B.	9 and 15
	C.	16
	D.	10
	E.	9
	F.	15

Answer 1

Using the data from the previous question on LDL cholesterol, you decide to test if the variance in LDL cholesterol of patients admitted to the hospital with a heart attack is the same as that of those who have not (the control). You use the R function var.test and obtain the following output.

   F test to compare two variances

data: ldl.ha and ldl.cont

F = 7.683, num df = 9, denom df = 15,
   p-value = 0.0006501

alternative hypothesis: true ratio of
variances is not equal to 1

95 percent confidence interval:

2.460444 28.960945

sample estimates:

ratio of variances

          7.683258

the null and alternative hypotheses are given by option D

H0: s12 = s22
H1: s12 ≠ s22

F test to compare two variancesUsing the data from the previous question on LDL cholesterol, you decide to test if the variance in LDL cholesterol of patients admitted to the hospital with a heart attack is the same as that of those who have not (the control). You use the R function var.test and obtain the following output.

data: ldl.ha and ldl.cont

F = 7.683, num df = 9, denom df = 15,
   p-value = 0.0006501

alternative hypothesis: true ratio of
variances is not equal to 1

95 percent confidence interval:

2.460444 28.960945

sample estimates:

ratio of variances

7.683258

Number of observations from each population we have

A ) 10 and 16