Subject # Brain Scaled Score WAIS-R IQ SCORE 1 50 100 2 60 115 3 65 120 4 40 96
ID: 3363737 • Letter: S
Question
Subject # Brain Scaled Score WAIS-R IQ SCORE
1 50 100
2 60 115
3 65 120
4 40 96
5 35 100
6 40 85
7 60 115
8 55 105
9 50 103
10 45 90
11 52 120
12 48 105
13 51 110
14 49 95
15 50 100
16 50 100
17 37 95
18 63 112
19 50 100
20 50 100
Explain how you would redesign the study to improve validity and reliability.
Explanation / Answer
Given that,
mean(x)=50
standard deviation , s.d1=8.1046
number(n1)=20
y(mean)=103.3
standard deviation, s.d2 =9.5317
number(n2)=20
null, Ho: u1 = u2
alternate, H1: u1 != u2
level of significance, = 0.05
from standard normal table, two tailed t /2 =2.093
since our test is two-tailed
reject Ho, if to < -2.093 OR if to > 2.093
we use test statistic (t) = (x-y)/sqrt(s.d1^2/n1)+(s.d2^2/n2)
to =50-103.3/sqrt((65.68454/20)+(90.8533/20))
to =-19.052
| to | =19.052
critical value
the value of |t | with min (n1-1, n2-1) i.e 19 d.f is 2.093
we got |to| = 19.05165 & | t | = 2.093
make decision
hence value of | to | > | t | and here we reject Ho
p-value: two tailed ( double the one tail ) - Ha : ( p != -19.0516 ) = 0
hence value of p0.05 > 0,here we reject Ho
ANSWERS
---------------
null, Ho: u1 = u2
alternate, H1: u1 != u2
test statistic: -19.052
critical value: -2.093 , 2.093
decision: reject Ho
p-value: 0
test is valid. we are using T test for difference of mean