Final Review Answers

Two-Tailed t Test Solution -1 H 0 : H a :  = df = Critical Value(s): Test Statistic: Decision:  = 368   = 24 t Reject H Reject at  =.05 P-value = 0

Two-Tailed Z Test Solution -2 H 0 : H a :  = n = Critical Value(s): Test Statistic: Decision:  = 70   Z Reject H Do not reject at  =.05

One-Tailed Z Test Solution -3 H 0 : H a :  = n = Critical Value(s): Test Statistic: Decision:  = 32  < Z Reject Reject at  =.01

Two-Tailed t Test Solution-4 H 0 : H a :   df  Critical Value(s): Test Statistic: Decision:  = 3.25   = 63 t Reject H Do not reject at  =.01

One-Tailed t Test Solution - 5 H 0 : H a :  = df = Critical Value(s): Test Statistic: Decision:  = 140  < = 19 t Reject H 0 Reject at  =.05

One-Tailed t Test Solution -6 H 0 : H a :  = df = Critical Value(s): Test Statistic: Decision:  = 5  < = 9 t Reject H 0 Do not reject at  =.05

One-Proportion Z Test Solution - 7 H 0 : H a :  = n = Critical Value(s): Test Statistic: Decision: p =.10 p < Z Reject H 0 Reject at  =.05

One-Proportion Z Test Solution - 8 H 0 : H a :  = n = Critical Value(s): Test Statistic: Decision: p =.04 p  Z Reject H Do not reject at  =.05

1.Miles per gallon ratings of cars before and after mounting radial tires - DEPENDENT 2.The life expectancy of light bulbs made in two different factories - INDEPENDENT 3.Difference in hardness between two metals: one contains an alloy, one doesn’t - INDEPENDENT 4.Tread life of two different motorcycle tires: one on the front, the other on the back - DEPENDENT 9

H 0 : H a :   df  Critical Value(s):  1 -  2 = 0 (  1 =  2 )  1 -  2  0 (  1   2 ) = 10 t Reject H Small-Sample Test Solution 10-A Test Statistic: Do not reject at  =.05

H 0 : H a :   df  Critical Value(s):  1 -  2 = 1% (  1 =  2 )  1 -  2  1% (  1   2 ) = 10 Small-Sample Test Solution 10-B Test Statistic: Do not reject at  =.05 t Reject H 0

Large-Sample Test Solution - 11 H 0 : H a :   n 1 =, n 2 = Critical Value(s): t Reject H  1 -  2 = 0 (  1 =  2 )  1 -  2  0 (  1   2 ) Do not reject at  =.10

Paired-Difference Solution-12 H 0 : H a :  = df = Critical Value(s):  d = 0 (  d =  A -  B )  d < = 3 t Reject H 0

Computation Table ObservationBeforeAfterDifference Sam85949 Tamika Brian78791 Mike87881 Total4 d = 1S d = 6.53

Test Statistic: Decision: Do not reject at  =.10

H 0 : H a :  = n 1 = n 2 = Critical Value(s): p 1 - p 2 = 0 p 1 - p 2  z Reject H Test for Two Proportions Solution -13

Reject at  =.01

H 0 : H a :  = n MA = n CA = Critical Value(s): p MA – p CA = 0 p MA – p CA < Z Reject H 0 Test for Two Proportions Solution - 14

Reject at  =.05