In: Statistics and Probability
A researcher conducted an experiment in which two independent random samples of students were asked to rate on a 7-point scale whether they thought animal research is wrong with 7 indicating it was wrong and 1 indicating it was not wrong. The sample sizes, means, and variances are shown separately for males and females in Table below.
Groups | N | Mean | Variance |
Females (Group 1) | 17 | 5.353 | 2.743 |
Males (Group 2) | 32 | 3.882 | 2.985 |
What is the correct calculated value for this test?
What is the correct critical value for this test?
For sample 1 :
x̅1 = 5.353
s12= 2.743
n1 = 17
For sample 2 :
x̅2 = 3.882
s22 = 2.935
n2 = 32
Null and Alternative hypothesis:
Ho : µ1 = µ2
H1 : µ1 ≠ µ2
Pooled variance :
S²p = ((n1-1)*s1² + (n2-1)*s2² )/(n1+n2-2)
= 2.9026
Test statistic:
t = (x̅1 - x̅2) / [√(s²p(1/n1 + 1/n2 )]
= 2.8769
df = n1+n2-2
= 47
Critical value :
At α = 0.05 and df = 47 , two
tailed critical value, t crit = T.INV.2T(0.02 , 47) = ± 2.012