Medical researchers are investigating if consumption of steroids increases stren
ID: 3310879 • Letter: M
Question
Medical researchers are investigating if consumption of steroids increases strength. Twenty-two weight lifters are recruited to participate in the study. Ten of the weight lifters are given high doses of steroids and asked to lift weights. The other 12 weight lifters are given sugar pills but they are told they are consuming steroids and asked to lift weights. After six months, the steroid group increased their bench press 140% with a standard deviation of 65%. The other group increased their bench by 95% with a standard deviation of 110%. Present the null hypothesis, the research hypothesis and test the null hypothesis using a t-statistic.
Explanation / Answer
Given that,
mean(x)=140
standard deviation , s.d1=65
number(n1)=10
y(mean)=95
standard deviation, s.d2 =110
number(n2)=22
null, Ho: u1 < u2
alternate, H1: u1 > u2
level of significance, = 0.05
from standard normal table,right tailed t /2 =1.833
since our test is right-tailed
reject Ho, if to > 1.833
we use test statistic (t) = (x-y)/sqrt(s.d1^2/n1)+(s.d2^2/n2)
to =140-95/sqrt((4225/10)+(12100/22))
to =1.443
| to | =1.443
critical value
the value of |t | with min (n1-1, n2-1) i.e 9 d.f is 1.833
we got |to| = 1.443 & | t | = 1.833
make decision
hence value of |to | < | t | and here we do not reject Ho
p-value:right tail - Ha : ( p > 1.443 ) = 0.09145
hence value of p0.05 < 0.09145,here we do not reject Ho
ANSWERS
---------------
null, Ho: u1 = u2
alternate, H1: u1 > u2
test statistic: 1.443
critical value: 1.833
decision: do not reject Ho
p-value: 0.09145
the steroid group increased their bench press than group with
sugar pills