Single Sample t Test Hand Out
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Transcript of Single Sample t Test Hand Out
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Single sample t statistic
Psychology 201 Prof. Rick Zinbarg
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The meaning of the t-test: A comparison of 2 studies Which one more likely to reject the null hypothesis? (answer without actually computing the t values)
Study 1 Study 2Subject Inteliagra Cortexin1 123 1222 122 1223 110 1104 110 1105 109 1096 109 1097 107 1078 106 1069 106 10610 106 10611 95 9512 95 9513 94 9414 94 9415 93 94M 105.27 105.27
H0 :X = 100H1 :X 100
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Ch. 12, Problem 9(p. 260)
1.
2.
H0 : = 5.3H1 : 5.3
Relative
Frequency
0 t
2
2
= .05,2 = .025df = n 1 = 10 1 = 9
t(.025) =
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Ch. 12, Problem 9(p. 260)
1.
2.
H0 : = 5.3H1 : 5.3
Relative
Frequency
0 t
2
2
RR: Reject Ho if t(obs) or t(obs)
t(.025) =
= .05,2 = .025df = n 1 = 10 1 = 9
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X=# of cigarettes smoked per day after new program
X X204
016
31
91
62
364
52
254
21
41
= 26 100
M = Xn=2610 =
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s =X2 ( X)
2n
n 1
=100 (26)
2
109
= 1.897
sM =sn
=1.89710
=
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t(obs ) =M 0sM
, sM =sn
3.
4. < -2.262 , therefore reject Ho.
The new therapy is effective at helping people reduce their smoking than the standard therapy
t(obs) =2.6 5.3.5999 =
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Using single sample t statistic to construct confidence intervals Use data from Ch. 12, #9 to construct a 95% CI for the of the # of cigarettes smoked per day after new program
(1 )%CI for = M t(2 )sM
#
$%
&
'(
1 = .95 = .052 =df = n1=101=
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.475
.475
.025
.025
Mobs2.6
t(.025)
-t(.025)
t(.025) = 2.262
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(1 )%CI for = 2.6 2.262 *.5999[ ]95%CI =