M Chap 13 Chegg Study Guided Sol X eztomheducationcomhmtpx P
Solution
We have given that shipping time is dependent variable (y) and distance is the dependent variable (x).
State the decision rule for alpha = 0.10 significance level
Given hypothesis is ,
H0 : <=0 Vs H1 : > 0
The test statistic is,
t = r * sqrt(n-2) / sqrt(1-r2)
where r is the sample correlation coefficient
n is the number of data pairs.
We can calculate r by using EXCEL
syntax : =CORREL(array1 , array2)
where array1 is distance and array2 is shipping time.
r = 0.310
t = 0.310 * sqrt( 20 - 2) / sqrt(1 - 0.3102)
t = 1.384
Now we have to find critical value by using t-distribution.
EXCEL syntax :
=tinv(probability , d.f.)
where probability = 2 * alpha
d.f. = n - 2
Critical value = 1.330
Reject H0 id t > 1.330
value of the test statistic is 1.384
% of variation in shipping time is explained by shipping distance is
r2 = 0.3102 = 0.096 = 0.10
105 of the variation in shipping time is explained by shipping distance.
