Answer:
I think the right answer is B.
Answer:
25
Step-by-step explanation:
We know that the standard error of the sampling distribution of sample means is
Standard error=standard deviation/√n
√n=standard deviation/Standard error
n=(standard deviation/Standard error)²
We are given that standard deviation=5 and standard error=1. So,
n=(5/1)²
n=5²
n=25.
Thus, the required sample size is 25.
Answer:
18 divided by 4.
Step-by-step explanation:
1/2x9= 4 1/2 and when you divide 18 divided by 4 you get 4 1/2 (4.5)
Answer:
464 grams.
Step-by-step explanation:
Amount of substance:
The amount of substance after t years is given by an equation in the following format:

In which A(0) is the initial amount and r is the decay rate, as a decimal.
Co-60 has a half life of 5.3 years.
This means that:

We use this to find r. So



![\sqrt[5.3]{(1-r)^{5.3}} = \sqrt[5.3]{0.5}](https://tex.z-dn.net/?f=%5Csqrt%5B5.3%5D%7B%281-r%29%5E%7B5.3%7D%7D%20%3D%20%5Csqrt%5B5.3%5D%7B0.5%7D)


So

If a pellet that has been in storage for 26.5 years contains 14.5g of Co-60, how much of this radioisotope was present when the pellet was put in storage?
We have that
, and use this to find A(0). So



[tex]A(0) = 464[tex]
464 grams.