Question

Two processes for manufacturing large roller bearings are under study. In both cases, the diameters (in centimeters) are being examined. A random sample of 21 roller bearings from the old manufacturing process showed the sample variance of diameters to be

s² = 0.246.

Another random sample of 28 roller bearings from the new manufacturing process showed the sample variance of their diameters to be

s² = 0.116.

Use a 5% level of significance to test the claim that there is a difference (either way) in the population variances between the old and new manufacturing processes.

(ii) Find the sample test statistic. (Round your answer to two decimal places.)

Answer 1

ald o old se new & o new S1²= 0.246 S² = 0.116 mi= 21 m2 = 28 Jest Statistic F S12 ~ Fmt, ma- 22 F = (0.246) (0.116) = 2.1207 2.1207] sample Test statistic = 2.1207 d=0.05 dy = 20,27 0.0347 [from Excel] Pvalue = P(F72.1207) = Since P value <0.05 between We There variance Reject is a of Ho signincant old and le. difference new process. Population