A manager wishes to check the meanmass of flour put into bags in his factory. He randomlysamples 10 bags and finds the meanmass is 1.478 kg and the standard deviation of thesample is 0.0196 kg.

$s_{n-1}=\sqrt{\frac{10}{9}}\times 0.0196=0.02066\dots$(M1)A1

[2 marks]

(1.463, 1.493) (M1)A1

Note: If $s_n$ used answer is (1.464, 1.492), award M1A0.

[2 marks]

95 % of the time these results would be produced by a populationwith mean of less than 1.5 kg, so it is likely the meanmass isless than 1.5 kg R1

[1 mark]