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
68.9 − 76.3
70 − 72
61.2 − 72.8
68 − 72
1 answer:
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Hey there!
3/4 means Rise/Run. Guess why the rise is called the rise and the run is called the run.
The 4 tells us to move 4 units in this direction:
------------------------------------------->
That was meant to represent an arrow.
Hope it helps!
The main idea is the number of marbles and the denominator of the probability. All you have to do is multiply the fraction by a fraction which is equal to 1 which makes the denominator equal to 63. We know 63 is a multiple of 9. 9 goes 7 times in 63 so we multiple the fraction with
which gives,
which when evaluated gives
and the numerator is the number of red marbles in the bag. So there are 14 red marbles in the bag :D