(Use Excel) A consumer advocate researches the length of life between two brands
ID: 3363771 • Letter: #
Question
(Use Excel) A consumer advocate researches the length of life between two brands of refrigerators, Brand A and Brand B. He collects data on the longevity of 40 refrigerators for Brand A and repeats the sampling for Brand B. These data are measured in years. Use Table 1.
Specify the competing hypotheses to test whether the average length of life differs between the two brands.
Using the appropriate commands in Excel, find the value of the test statistic. Assume that A2 = 4.5 andB2 = 6.3. What is the p-value? (Negative values should be indicated by a minus sign. Do not round intermediate calculations. Enter "Test statistic" value in 2 decimal places and "p-value" in 4 decimal places.)
(Use Excel) A consumer advocate researches the length of life between two brands of refrigerators, Brand A and Brand B. He collects data on the longevity of 40 refrigerators for Brand A and repeats the sampling for Brand B. These data are measured in years. Use Table 1.
Explanation / Answer
Given that,
mean(x)=17.98
standard deviation , 1 =2.121
number(n1)=40
y(mean)=18.58
standard deviation, 2 =2.5099
number(n2)=40
null, Ho: u1 = u2
alternate, H1: 1 != u2
level of significance, = 0.05
from standard normal table, two tailed z /2 =1.96
since our test is two-tailed
reject Ho, if zo < -1.96 OR if zo > 1.96
we use test statistic (z) = (x-y)/sqrt(s.d1^2/n1)+(s.d2^2/n2)
zo=17.98-18.58/sqrt((4.49864/40)+(6.2996/40))
zo =-1.15
| zo | =1.15
critical value
the value of |z | at los 0.05% is 1.96
we got |zo | =1.155 & | z | =1.96
make decision
hence value of | zo | < | z | and here we do not reject Ho
p-value: two tailed ( double the one tail ) - Ha : ( p != -1.15 ) = 0.24818
hence value of p0.05 < 0.24818,here we do not reject Ho
ANSWERS
---------------
null, Ho: u1 = u2
alternate, H1: 1 != u2
test statistic: -1.15
critical value: -1.96 , 1.96
decision: do not reject Ho
p-value: 0.24818
Do not reject H0, there is no evidence that the average life differs between the brands
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