| Exam Board | OCR |
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| Module | Stats 1 (Statistics 1) |
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| Year | 2018 |
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| Session | December |
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| Topic | Measures of Location and Spread |
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| Type | Adding data values |
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13 The marks of 24 students in a test had mean \(m\) and standard deviation \(\sqrt { 6 }\). Two new students took the same test. Their marks were \(m - 4\) and \(m + 4\).
Show that the standard deviation of the marks of all 26 students is 2.60 , correct to 3 significant figures.