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Is wine good for your heart? A researcher from the University of California, San Diego, collected data on average per capita wine consumption and heart disease death rate in a random sample of 19 countries for which data were available. The following table displays the data.

(a) Is there statistically significant evidence of a negative linear relationship between wine consumption and heart disease deaths in the population of countries? Carry out an appropriate significance test at the α=0.05level.

(b) Calculate and interpret a 95% confidence interval for the slope β of the population regression line.

Short Answer

Expert verified

a) There is sufficient evidence to support the claim that there is a negative linear relationship between wine consumption and heart disease deaths in the population of countries.

b)(-30.4743,-15.4637)

Step by step solution

01

Given Information(Part b)

Given:

n=Sample size=19

c=Confidence level=95%

02

Explanation(Part b)

The estimate of the slope is given in the row "X Variable 1 and in the column "Coefficients" of the output:

b≈-22.969

The estimate of the standard error of the slope is given in the row "X Variable 1 and in the column "standard error" of the output:

SEb≈3.557

The degrees of freedom is the sample size decreased by 2 :

localid="1650543375677" df=n-2=19-2=17

The critical t-value can be found in table B in the row of d f=17 and in the column of c=95% :

t*=2.110

The boundaries of the confidence interval then become:

localid="1650543397407" b-t*×SEb=-22.969-2.110×3.557=-30.4743

localid="1650543408380" b+t*×SEb=-22.969+2.110×3.557=-15.4637

03

Given Information(Part a)

Given:

n=19

b=-22.969

SEb=3.557

04

Explanation(Part a)

Determine the hypothesis:

β=0

β<0

Compute the value of the test statistic:

localid="1650543432666" t=b-β0SEb=-22.969-03.557≈-6.457

The P-value is the probability of obtaining the value of the test statistic, or a value more extreme. The P-value is the number (or interval) in the column title of Table B containing the t-value in the row d f=n-2=19-2=17 :

P<0.0005

If the P-value is less than or equal to the significance level, then the null hypothesis is rejected:

P<0.05⇒RejectH0

There is sufficient evidence to support the claim that there is a negative linear relationship between wine consumption and heart disease deaths in the population of countries.

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