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Calculate estimated values for the mean and the standard deviation of the reading times.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
A newspaper article was read by 120 people. The times they took, correct to the nearest second, are shown in the table below: Time (seconds) $1$-$25$, $26$-$35$, $36$-$45$, $46$-$55$, $56$-$90$; Number of people $4$, $24$, $38$, $34$, $20$.
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