4 Oscar is studying the daily maximum temperature in \({ } ^ { \circ } \mathrm { C }\) in a village during the month of June.
He constructs a \(95 \%\) confidence interval of width \(0.8 ^ { \circ } \mathrm { C }\) using a random sample of 150 days.
He assumes that the daily maximum temperature has a normal distribution.
4
- Find the standard deviation of Oscar's sample, giving your answer to three significant figures.
4 - Oscar calculates the mean of his sample to be \(25.3 ^ { \circ } \mathrm { C }\)
He claims that the population mean is \(26.0 ^ { \circ } \mathrm { C }\)
Explain whether or not his confidence interval supports his claim.
4 - Explain how Oscar could reduce the width of his 95\% confidence interval.