Moderate -0.3 This is a straightforward confidence interval calculation with small sample size requiring t-distribution. Students must calculate sample mean and standard deviation, then apply the standard formula with t₇ critical value. While it involves multiple computational steps (6 marks), it's a direct application of a standard procedure with no conceptual challenges or novel problem-solving required, making it slightly easier than average.
The heights, in metres, of a random sample of 8 trees of a particular type are as follows.
14.2 11.3 10.8 8.4 12.8 11.5 12.1 9.2
Assuming that heights of trees of this type are normally distributed, calculate a 95% confidence interval for the mean height of trees of this type.
[6]
The heights, in metres, of a random sample of 8 trees of a particular type are as follows.
14.2 11.3 10.8 8.4 12.8 11.5 12.1 9.2
Assuming that heights of trees of this type are normally distributed, calculate a 95% confidence interval for the mean height of trees of this type.
[6]
\hfill \mbox{\textit{CAIE FP2 2018 Q6 [6]}}