8.The final scores of games of a certain sport were compared against the final point spreads established by oddsmakers. The difference between the game outcome and point spread (called a point-spread error) was calculated for 220 games. The sample mean and sample standard deviation of the point-spread errors are x overbarxequals=1.5 and sequals=13.3.

Use this information to test the hypothesis that the true mean point-spread error for all games is larger than 00 Conduct the test at alphaequals=0.10 and interpret the result.Determine the null and alternative hypotheses. Choose the correct answer below.

A.

Upper H 0H0:

mu 00not equals0

Upper H Subscript aHa:

mu 00equals=0

B.

Upper H 0H0:

mu 00equals=0

Upper H Subscript aHa:

mu 00greater than>0

C.

Upper H 0H0:

mu 00equals=0

Upper H Subscript aHa:

mu 00less than<0

D.

Upper H 0H0:

mu 00equals=0

Upper H Subscript aHa:

mu 00not equals0

9.When bonding teeth, orthodontists must maintain a dry field. A new bonding adhesive has been developed to eliminate the necessity of a dry field. However, there is concern that the new bonding adhesive is not as strong as the current standard, a composite adhesive. Tests on a sample of

8 extracted teeth bonded with the new adhesive resulted in a mean breaking strength (after 24 hours) of

x overbarxequals=5.55Mpa and a standard deviation of sequals=0.32

Mpa. Orthodontists want to know if the true mean breaking strength is less than 6.16Mpa, the mean breaking strength of the composite adhesive.a. Set up the null and alternative hypotheses for the test. Choose the correct answer below.

A.

Upper H 0H0:

mugreater than or equals6.16

vs.

Upper H Subscript aHa:

muless than<6.16

B.

Upper H 0H0:

muequals=6.16

vs.

Upper H Subscript aHa:

muless than<6.16

C.

Upper H 0H0:

muequals=6.16

vs.

Upper H Subscript aHa:

munot equals6.16

D.

Upper H 0H0:

muequals=5.55

vs.

Upper H Subscript aHa:

munot equals5.55

E.

Upper H 0H0:

muequals=5.55

vs.

Upper H Subscript aHa:

muless than<5.55

F.

Upper H 0H0:

muequals=6.16

vs.

Upper H Subscript aHa:

mugreater than>6.16

10.recent study investigated tractor skidding distances along a road in a forest. The skidding distances (in meters) were measured at 20 randomly selected road sites. The data are given in the accompanying table. A logger working on the road claims that the mean skidding distance is at least

425 meters. Is there sufficient evidence to refute this claim? Use

alphaequals=0.10State the hypotheses to test the claim that the mean skidding distance is at least

425meters. Choose the correct answer below.

A.

H0:

muequals=425

Ha:

munot equals425

B.

H0:

muequals=425

Ha:

muless than<425

C.

H0:

munot equals425

Ha:

muequals=425

D.

H0:

muequals=425

Ha:

mugreater than>425

11.A business journal investigation of the performance and timing of corporate acquisitions discovered that in a random sample of 2,980 firms, 785announced one or more acquisitions during the year 2000. Does the sample provide sufficient evidence to indicate that the true percentage of all firms that announced one or more acquisitions during the year 2000 is less than 29%? Use alphaequals=0.10to make your decision.What are the hypotheses for this test?

A.

Upper H 0 : p equals 0.29H0:p=0.29

Upper H Subscript a Baseline : p less than 0.29Ha:p<0.29

B.

H0: pequals=0.29

Ha: pnot equals0.29

C.

H0:

pgreater than>0.29

Ha: pless than or equals0.29

D.

H0: pnot equals0.29

Ha: pequals=0.29

E.

H0: pequals=0.29

Ha: pgreater than>0.29

F.

H0: pless than<0.29

Ha: pequals=0.29

12.In a representative sample of 889 coffee growers from Country X, 492 growers were certified to sell to organic coffee markets while 96growers were transitioning to become organic certified. In Country Y,

69% of coffee growers are organic certified. Is there evidence to indicate that fewer than

69% of the coffee growers in Country X are either organic certified or transitioning to become organic certified? State your conclusion so that there is only a 5% chance of making a Type I error.

What are the hypotheses for this test?

A.

H0: pnot equals0.69

Ha: pequals=0.69

B.

Upper H 0 : p equals 0.69H0:p=0.69

Upper H Subscript a Baseline : p less than 0.69Ha:p<0.69

C.

H0: pequals=0.69

Ha: pgreater than>0.69

D.

H0: pequals=0.69

Ha: pnot equals0.69

E.

H0: pgreater than>0.69

Ha: pless than or equals0.69

F.

H0: pless than<0.69

Ha: pequals=0.69