In a study of 225 adults, the average heart rate was 72 beats per minute. Assume the population of heart rates is known to be approximately normal, with a standard deviation of 10 beats per minute. What does a margin of error of 1.1 for the 90% confidence interval of the average beats per minute mean?
a There is a 90% chance that the population mean is between 70.9 and 73.1 beats per minute.
b There is a 90% chance that the population mean is between 62 and 82 beats per minute.
c There is a 10% chance that the population mean is less than 72 beats per minute.
d There is a 10% chance that the population mean is more than 72 beats per minute.