When subjects were treated with a drug their systolic blood

When subjects were treated with a drug, their systolic blood pressure readings (in mm Hg) were measured before and after the drug was taken. Results are given in the table below. Assume that the paired sample data is a simple random sample and that the differences have a distribution that is approximately normal. Using a 0.01 significance level, is there sufficient evidence to support the claim that the drug is effective in lowering systolic blood pressure?

Before/ After
188 179
189 155
179 165
175 162
159 163
205 143
157 152
179 147
183 144
210 179
169 186
168 183

In this example,?

?d?

is the mean value of the differences d for the population of all pairs of data, where each individual difference d is defined as the systolic blood pressure reading before the drug was taken minus the reading after the drug was taken. What are the null and alternative hypotheses for the hypothesis test?

A. H0: ?d=0       H1: ?d>0

B. H0: ?d?0       H1:?d=0

C. H0: ?d?0      H1:?d>0

D. H0: ?d=0      H1:?d<0

Identify the test statistic.

t= _______

(Round to two decimal places as needed.)

Identify the P-value.

P-value= _______

(Round to three decimal places as needed.)

Since the P-value is      Less///or////Greater_____??than the significance level, Fail to Reject////or///Reject Ho.

There is?Insufficient//or//sufficient____?evidence to support the claim that the drug is effective in lowering systolic blood pressure.

?

H0.?

There is?

?evidence to support the claim that the drug is effective in lowering systolic blood pressure.

Solution

A. H0: ?d=0       H1: ?d>0

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The test statistic is

t=mean difference/(s/vn)

=16.917/(23.496/sqrt(12))

=2.49

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It is a right-tailed test.

The degree of freedom =n-1=12-1=11

So the p-value= P(t with df=11>2.49) = 0.015 (from student t table)

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Since the P-value is      Greater___?than the significance level, Fail to Reject Ho.

There is?Insufficient evidence to support the claim that the drug is effective in lowering systolic blood pressure.