Paper 7 October/November 2010 MATHEMATICS (9709/71) A Levels
لطفا برای اطمینان از عملکرد و تجربه بهتر از مرورگرهای مدرن و به روز مانند کروم یا فایرفاکس استفاده کنید.

Past experience has shown that the heights of a certain variety of rose bush have been normally distributed with mean $85.0{\text{ }}cm$. A new fertiliser is used and it is hoped that this will increase the heights. In order to test whether this is the case, a botanist records the heights, $x{\text{ }}cm$, of a large random sample of $n$ rose bushes and calculates that $\overline x = 85.7$ and $s = 4.8$, where $\overline x $ is the sample mean and ${s^2}$ is an unbiased estimate of…