Answer:
<em>11.29 grams </em><em>of strontium-90 were present in the original rock sample in 1933.</em>
Step-by-step explanation:
Strontium has a half-life of 28.8 years. Therefore,
1989 - 1933 = 56 years.
56 / 28.8 = 1.94 half-lives
Thus, the quantity of the radioisotope remaining will double for each half-life elapsed. moving backwards in time.
Therefore, moving backwards in time by 1.94 half-lives, the quantity remaining will double by 1.94 times.
Thus, the amount remaining in 1933 is
3.0 × (1.94)² = <em>11.29 grams</em>
Answer:
a)Slope:
Intercept:
b)
And the determination coeffecient is
Step-by-step explanation:
Data given and definitions
The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.
The sum of squares "is the sum of the square of variation, where variation is defined as the spread between each individual value and the grand mean"
When we conduct a multiple regression we want to know about the relationship between several independent or predictor variables and a dependent or criterion variable.
n=110,

Part a
The slope is given by this formula:
If we replace we got:
We can find the intercept with the following formula
We can find the average for x and y like this:
And replacing we got:
Part b
In order to calculate the correlation coefficient we can use this formula:
For our case we have this:
n=110,
So we can find the correlation coefficient replacing like this:
And the determination coeffecient is
Answer:
1021
Step-by-step explanation:
delta math said it was right
Answer: 
Step-by-step explanation:
The formula for calculate the volume of a cylinder is:

Where "r" is the radius and "h" is the height.
Make the conversion from inches to feet. Since
,you get:

So in this case you can identify that:

Then, substituting them into the formula and simplifying you get:

Therefore, the expression for the volume of L feet of drainage tubing, in cubic feet is:
