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Il '''Test Q''' (''Q-Test'', in [[lingua inglese|inglese]]) è un semplice test [[statistica|statistico]] per scartare dati ritenuti errati.
Per effettuare il '''Test Q''' al fine di individuare i dati errati, si devono disporre i dati in ordine di valore crescente, e quindi per ognuno calcolare il coefficiente Q, definito come:
To apply a '''Q test''' for bad data, arrange the data in order of increasing values and calculate Q as defined:
:<math>QQ_n=\frac{gap|x_n-x_{n-1}|}{rangeR}</math>
dove R è l'intervallo in cui abbiamo dei valori
If Q<sub>calculated</sub> > Q<sub>table</sub> then reject the questionable point.
==Tabella di valori==
==Table==
<td {|style="vertical-align: top;" >Q<sub>95%</sub>:<br>▼<table>
|Number of Values:
<tr>
<td| style="verticaltext-align: topcenter;">Number of Values:</td>|3
<td| style="vertical-align: top; text-align: center;"> 3<br>|4
<td| style=" vertical-align: top; text-align: center;" >7<br>|5▼</td>
<td| style="vertical-align: top; text-align: center;">4<br>|6
<td |style=" vertical-align: top; text-align: center;" >0.507<br>|7▼</td>
<td |style="vertical-align: top; text-align: center;">5<br>|8
<td |style=" vertical-align: top; text-align: center;" >0.468<br>|9▼</td>
<td |style="vertical-align: top; text-align: center;">6<br>|10
|-
</td>
|Q<sub>90%</sub>:
▲<td style="vertical-align: top; text-align: center;">7<br>
<td |style=" vertical-align: top; text-align: center;" >|0. 437<br>941▼</td>
<td |style="vertical-align: top; text-align: center;">8<br>|0.765
<td |style=" vertical-align: top; text-align: center;" >|0. 412<br>642▼</td>
<td |style="vertical-align: top; text-align: center;">9<br>|0.560
<td |style=" vertical-align: top; text-align: center;" >|0. 970<br>507▼</td>
<td |style="vertical-align: top; text-align: center;">10<br>|0.468
<td |style=" vertical-align: top; text-align: center;" >|0. 829<br>437▼</td>
<td |style=" vertical-align: top; text-align: center;" >|0. 710<br>412▼</tr>
|-
<tr>
<td style="vertical-align: top;">|Q<sub>9095%</sub>:<br>
<td |style=" vertical-align: top; text-align: center;" >|0. 625<br>970▼</td>
<td |style="vertical-align: top; text-align: center;">|0.941<br>829
<td |style=" vertical-align: top; text-align: center;" >|0. 568<br>710▼</td>
<td |style="vertical-align: top; text-align: center;">|0.765<br>625
<td |style=" vertical-align: top; text-align: center;" >|0. 526<br>568▼</td>
<td |style="vertical-align: top; text-align: center;">|0.642<br>526
<td |style=" vertical-align: top; text-align: center;" >|0.493 <br>▼</td>
<td |style="vertical-align: top; text-align: center;">|0.560<br>466
|}
</td>
▲<td style="vertical-align: top; text-align: center;">0.507<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.468<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.437<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.412<br>
</td>
</tr>
<tr>
▲<td style="vertical-align: top;">Q<sub>95%</sub>:<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.970<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.829<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.710<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.625<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.568<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.526<br>
</td>
▲<td style="vertical-align: top; text-align: center;">0.493<br>
</td>
<td style="vertical-align: top; text-align: center;">0.466<br>
</td>
</tr>
</table>
==Example==
With 10 observations at 90% confidence, Q<sub>calculated</sub> < Q<sub>table</sub>. Therefore keep 0.169 at 90% confidence.
''See also:'' [[List of statistical topics]]
==Voci correlate==
[[categoria:statistica]]
[[en:Q test]]
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