Answer:
The combined standard deviation is 1.58114.
Step-by-step explanation:
The formula to compute the combined standard deviations of two different data sets is:

Here
is the combined mean given by:

It is provided that the sample size is same for both the data sets, i.e.
Compute the combined mean as follows:

Compute the combined standard deviation as follows:

Thus, the combined standard deviation is 1.58114.
Answer:
Brain travelled 687.68 from the cliff.
Step-by-step explanation:
Given that:
Height of the cliff = 520
Base of the cliff = 450
The distance will form the hypotenuse of right angled triangle.
Pythagorean theorem states square of hypotenuse of right angled triangle is equal to the sum of squares of base and height of triangle.
Using pythagorean theorem;
a = 520, b=450, c = hypotenuse

Taking square root on both sides

Hence,
Brain travelled 687.68 from the cliff.
Answer:
C, D
Step-by-step explanation:
1/5 is .20 which is 20%
4/20 is equal to 1/5 which is 20%
Hope this helps
Answer: 200 feet
Step-by-step explanation:
1000feet/5feet= 200feet