Question

In a study of 250 adults, the mean heart rate was 70 beats per minute. Assume the population of heart rates is known to be approximately normal with a standard deviation of 12 beats per minute. What is the 99% confidence interval for the mean beats per minute?
68.9 – 76.3

70 – 72

61.2 – 72.8

68 – 72

Answer 1

Can anyone help? :(

Answer 2

The 99% confidence interval is given by:
\[\large \bar{x}-2.576\frac{\sigma}{\sqrt{n}},\ \bar{x}+2.576\frac{\sigma}{\sqrt{n}}\]
Just plug in the given values.

Answer 3

What goes where?

Answer 4

Does 70 go into o and 12 go into n? or vice versa?

Answer 5

If you are studying statistics you should be familiar with these symbols:
\[\large \bar{x}=70\]
\[\large \sigma=12\]
\[\large n=250\]

Answer 6

ok so