Answer:
(30.09, 32.91)
Step-by-step explanation:
Mean number of pounds of trash = x = 31.5 pounds
Standard deviation = s = 7.8 pounds
Sample size = n = 120
Confidence level = 95%
Since, we are given the sample standard deviation instead of the population standard deviation, we will use t-test to find the confidence interval.
Degrees of freedom = df = n - 1 = 120 - 1 = 119
The t-value associated with 95% confidence interval and df=119 from the t-table comes out to be:
t = 1.98
The formula to calculate the confidence interval is:

Using the values in above expression we get:

Thus, the 95% confidence interval for the mean number of lbs of trash per person per week that is generated in the city is (30.09, 32.91)
Answer: $820
Step-by-step explanation:
Use a proportion
9.5/100 = 77.90/x
Multiply 77.90 times 100 and divide by 9.5, the answer is $820
The notation just means
(f/g)(-4) = f(-4) / g(-4)
If f(x) = x² + 2 and g(x) = 1 - 3x, then
f(-4) = (-4)² + 2 = 16 + 2 = 18
g(-4) = 1 - 3 (-4) = 1 + 12 = 13
and so
(f/g)(-4) = 18/13