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 appro
ximately 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
The z score for a confidence level of 99% is 2.575.. You need to know this to complete this type of problem.. the other two commonly used confidence levels are 90% and 95% having z scores of 1.645 and 1.96 respectively. You need to memorize this!
To find the confidence interval, it will be defined as the sample mean plus/minus the margin of error.. Now to find the margin of error, divide the standard deviation of 12 by the square root of the number of elements in your sample(√250). Then take that result and multiply it by the Z score I mentioned above for a 99% confidence level.
In this case: the sample mean is 70 and the margin of error is approximately 1.95
So to calculate the confidence interval, do the following: 70 - 1.95 = 68.05 rounded to the nearest whole number is 68 70 + 1.95 = 71.95 rounded to the nearest whole number is 72
Looks like that would be the last choice. hope this helps.. it's been awhile since my work with statistics :-)
<span>It is required to find the highest altitude (in meters) . </span> For the given <span>quadratic function ⇒⇒ A(t) = −(t − 11)² + 115</span> From the attached figure which represents the graph of the given function the maximum will be at point (11,115)
So, <span>the highest altitude (in meters) = 115 meter </span> <span>and it will reach it at t = 11 </span><span>seconds</span>
The ground is supplementary. That means it equals 180 degrees. (A circle is 360. The ground is half the circle) So u set up the equation as 180=22x+14x 180=36x /36 /36 5=x
But you need to find the 14x 14(5) =70 degrees before the tree hits the ground
