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A study was conducted to determine the effectiveness of a certain treatment. A group of 112

112 patients were randomly divided into an experimental group and a control group. The table shows the result for their net improvement. Let the experimental group be group 1 and the control group be group 2.

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Click the icon to view the net improvement results.

(a) Test whether the experimental group experienced a larger mean improvement than the control group at the alpha equals 0.01

=0.01 level of significance.

State the null and alternative hypotheses. Choose the correct answer below.

A.

Upper H 0 : mu 1 equals mu 2

H0:1=2 and Upper H 1 : mu 1 not equals mu 2

H1:12

B.

Upper H 0 : mu 1 equals mu 2

H0:1=2 and Upper H 1 : mu 1 greater than mu 2

H1:1>2

C.

Upper H 0 : mu 1 equals mu 2

H0:1=2 and Upper H 1 : mu 1 less than mu 2

H1:1<2

Determine theP-value for this hypothesis test.

P-valueequals

=

nothing

(Round to three decimal places asneeded.)

Choose the correct conclusion.

A.

Do not reject

Donotreject Upper H 0

H0. There is not

isnot sufficient evidence at the alpha

equals

=0.01

0.01 level of significance to say that the experimental group experienced a larger mean improvement than the control group.

B.

Do not reject

Donotreject Upper H 0

H0. There is

is sufficient evidence at the alpha

equals

=0.01

0.01 level of significance to say that the experimental group experienced a larger mean improvement than the control group.

C.

Reject

Reject Upper H 0

H0. There is

is sufficient evidence at the alpha

equals

=0.01

0.01 level of significance to say that the experimental group experienced a larger mean improvement than the control group.

D.

Reject

Reject Upper H 0

H0. There is not

isnot sufficient evidence at the alpha

equals

=0.01

0.01 level of significance to say that the experimental group experienced a larger mean improvement than the control group.

(b) Construct a 90

90% confidence interval about mu 1 minus mu 2

12 and interpret the results.

(

nothing

,

nothing

) (Round to two decimal places asneeded.)

What is the interpretation of this confidenceinterval?

A.

We are 90

90% confident that the difference of the means is in the interval.

B.

We are 90

90% confident that the difference between randomly selected individuals will be in the interval.

C.

There is a 90

90% probability that the difference between randomly selected individuals will be in the interval.

D.

There is a 90

90% probability that the difference of the means is in the interval.

Click to select your answer(s).

Net Improvement

Experimental Control

n

51 61

14.1 5.5

8.1 2.8