A researcher has collected blood pressure measurements from a small sample of older people living in aged care facilities. The recorded blood pressure measurements (measured in millimetres of mercury, mmHg) were:
Y = (90, 74, 87, 100, 70, 99, 85, 76, 60, 92)
A previous study, based on a very large number of individuals living in aged care facilities found that the population variance to be σ2 = 142.46 mmHg. Assume that Y follows a Gaussian distribution, calculate the upper limit bound of the 99% confidence interval (two-sided) for the mean blood pressure in the collected sample.
Please help me,
my approach is :
my calculated mean is sigma y/n and where n = 10
and so after this using i should calculate for 95% interval and use z table?