Question

Use the given information to find the number of degrees of freedom, the critical values x2/l and x 2/r and the confidence interval estimate of o. Nicotine in menthol cigarettes 98%; n=22 s= 0.21mg

Answer 1

Degree of freedom = 22 - 1 = 21

Crtical values

χ2 (1 - 0.02/2, 22 - 1) ) = 8.8972 ( left )

χ2 (0.02/2, 22 - 1 ) = 38.9322 ( right )

χ2 (0.02/2, 22 - 1 ) = 38.9322
χ2 (1 - 0.02/2, 22 - 1) ) = 8.8972
Lower Limit = (( 22-1 ) 0.0441 / χ2 (0.02/2) ) = 0.0238
Upper Limit = (( 22-1 ) 0.0441 / χ2 (0.02/2) ) = 0.1041
98% Confidence interval is ( 0.0238 , 0.1041 )
( 0.0238 < σ2 < 0.1041 )
( 0.1542 < σ < 0.3226 )