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for 90 % confidence interval is 1.65.Step 1:
\The mean of Wechsler IQ test desingned for adults μ is 100.
\The standard deviation of Wechsler IQ test desingned for adults σ is 15.
\90 % confidence interval of sample mean is less than 3 IQ.
\Here margin of error E is 3.
\ for 90 % confidence interval is 1.65.
Margin of error : ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=7b0fc7ca65810328bed2141e605dd116.png\")
,
where Z is the Z-score for 90 % of confidence interval.
\σ is the standard deviation
\μ is the mean
\n is sample size.
\Step 2:
\Find the sample size.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=926f3a1583a53ebb9f0d42189b79fc72.png\")
Sample size of the Wechsler IQ test desingned for adults is 68.
\Solution:
\Sample size of the Wechsler IQ test desingned for adults is 68.