<PRE><B>Question 1193959</B>
Here is 2. 
Ho: change - or same
Ha: change +.
alpha=0.10 p{reject Ho|Ho true}
test stat is a t (paired t) df=9
t=(difference/sd/sqrt(10)
mean is 6.9 sd=5.43
test stat is 6.9/5.43/sqrt(10)=4.01 highly significant at the 0.10 level
-
Home phone
Ho: mu men=mu women
Ha: not equal
alpha=0.05 p{reject Ho|Ho true}
test stat is a 2 sample t df=198 with C.V actually a little more than 1.96 but will use that value
t=(diff in means)/sqrt{(sigma 1^2/n1+sigma2^2/n2)}
pooled sd: {{ (n1-1)s1^2+(n2-1)s2^2/(n1+n2-2 }}=sqrt(99*10000+99*22500)=127.47 min pooled sd
so t=-176/127.47 sqrt(2/100)=-176/18.03=-9.76
This is highly significant at the 0.05 level p &lt;&lt;0.0001

Cell phone
difference in means is +97 (men-women)
pooled sd is sqrt (99*120^2+99*100^2)=110.45
and the denominator is 110.45*sqrt(.02)=15.62
the quotient is 6.21 and this is highly significant.
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