Answer:
She started with 200 stamps
Step-by-step explanation:
Answer:
c=-9x^2-15x
Step-by-step explanation:
A. Stiles. For Melendez, each family member uses about 390 kilowatts of electricity. For Barton, each family member uses about 355 kilowatts of energy. Stiles uses 745 kilowatts per family member. 745 divided by 355 rounds up to 2 while 745 divided by 390 rounds up to 2. This means that the Stiles family uses twice the amount of electricity per person than the other families.
b. The Melendez family. The Melendez family uses 875 gallons per family member. The Barton family uses about 1067 gallons of water while the Stiles family uses about 1250 gallons. 875< 1067< 1250. This means that the Melendez family uses the least amount of water per family member.
Answer:
We need a sample size of least 119
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
95% confidence level
So , z is the value of Z that has a pvalue of , so .
Sample size needed
At least n, in which n is found when
We don't know the proportion, so we use , which is when we would need the largest sample size.
Rounding up
We need a sample size of least 119