Answer:
54.80 MPa to 55.92 MPa
Step-by-step explanation:
Sample mean fracture strength (x) = 55.36 MPa
Sample standard deviation (s) = 3.99 MPa
Sample size (n) = 196.
The upper and lower bounds for a 95% confidence interval are given by:
The upper and lower bounds of the confidence interval are;
The 95% confidence interval for true average fracture strength is 54.80 MPa to 55.92 MPa
Answer:
1222 billion dollars.
Step-by-step explanation:
To find the total increase from 1960 to 2010, we need to find the growth of each decade and sum them all:
In the period 1960-1970, we have x = 1, and the growth is:
In the period 1970-1980, we have x = 2, and the growth is:
The growth in the following 3 periods are:
So the total growth in the period 1960 - 2010 is:
Rounding to the nearest billion dollars, we have a total of 1222 billion dollars.