7 The rainfall per day in February in a particular town has been recorded as having a mean of 1.8 inches.
Sienna claims that rainfall in February has increased in the town. She records the rainfall in a random sample of 12 days.
Her sample mean is 2 inches and her sample standard deviation is 0.4 inches.
It is assumed that rainfall per day has a normal distribution.
7
- Investigate Sienna's claim using the \(5 \%\) level of significance.
7 - For the test carried out in part (a), state in context the meaning of a Type II error.
7
- The distribution of rainfall per day in February in the town over 10 years is shown in the histogram.
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Explain whether or not the assumption that rainfall per day in February has a normal distribution is appropriate.