Two different brands of batteries are tested and the variati

Two different brands of batteries are tested and the variations of their voltage outputs are noted. The table gives the data. At a 5% significance level, thest the claim that the populations of the two brands have the same voltage variations.

1) Give the null and alternate hypotheses.

2) Find the critical value of this F-test.

3) Find the test value for the variances.

4) What is your decision?   (reject or do not reject)

5) What is the conclusion? (equal or not equal)

Solution

1)

Null Hypothesis : V1 =V2

Alternate hHypothesis = V1 NOT=V2

2)

dF1 = 10-1 =9

dF2 =8-1 =7

alpha =0.05

Therefore,

Critical value = 3.6767 Answer

3)

F-value = s1^2 / s2^2

= (0.37)^2 / (0.31)^2

= 1.425 Answer

4)

F-value < Critical Value

Hence ,

Reject null hypothesis.

5)

Not Equal