# Statistics Questions and Answers

Math

StatisticsYou want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately o = 20.8. You would like to be 90% confident that your estimate is within 2 of the true population mean. How large of a sample size is required? n || Do not round mid-calculation. However, you are encouraged to use a critical value accurate to three decimal places - this is important for the system to be able to give hints for incorrect answers.

Math

StatisticsYou want to obtain a sample to estimac population mean. Based on previous evidence, you believe the population standard deviation is approximately o = 29.4. You would like to be 90% confident that your estimate is within 3 of the true population mean. How large of a sample size is required?
n =
Do not round mid-calculation. However, you are encouraged to use a critical value accurate to three decimal places - this is important for the system to be able to give hints for incorrect answers.

Math

StatisticsYou want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately o = 60.5. You would like to be 99% confident that your estimate is within 3 of the true population mean. How large of a sample size is required?
n=
Do not round mid-calculation. However, you are encouraged to use a critical value accurate to three decimal places - this is important for the system to be able to give hints for incorrect answers.

Math

StatisticsAdelaide wants to buy a new generator. The generator costs $2750. Adelaide decides to finance the generator for 36 months at an APR of 11.5%. Determine Adelaide's monthly payment. Round your answer to the nearest cent, if necessary.

Math

StatisticsFind the numerical value of the area under the normal curve given the following information:
▪ between 1.23 and 2.01 standard deviations above the mean
enter your answer as a decimal (NOT percentage) and lead with a zero...for example: 0.1234

Math

StatisticsThe intelligence of the clones of Jango Fett are deteriorating at a rate that has a standard distribution. If the average I.Q of a clone is 90 with a standard diviation of 2.6, what percent of the clones are smarter than a clone with an I.Q of 85? (round to the nearest hundredth.)
% are smarter than a clone with an I.Q of 85.

Math

StatisticsThe power of Darth Vader using the force can lift a speeder 14m off the ground with a thought. The average Sith can lift a speeder 10 meters with a standard deviation of 1.2. This data fits a standard distribution. What is Vader's z-score? (Round to the nearest 10th.)
Z= type your answer...

Math

StatisticsSuppose the supply and demand for a certain DVD are given by p=1/6 q2 and p = -1/6q2+44, respectively, where p is price and q is quantity. Find the equilibrium price.
A. $26
B. The supply and demand curves do not intersect.
C. $24
D. $21
E. $22

Math

StatisticsFind the mean of the following data set. Assume the data set is a sample. Round your answer to the nearest hundredth, if necessary.
22, 29, 30, 35, 18, 30, 31, 24, 28, 25, 25

Math

StatisticsThe fox population in a certain region has an annual growth rate of 9 percent per year. It is estimated that the population in the year 2000 was 11800.
(a) Find a function that models the population t years after 2000 (t = 0 for 2000).
Your answer is P(t) =
(b) Use the function from part (a) to estimate the fox population in the year 2008.
Your answer is (the answer should be an integer)

Math

StatisticsEach voter in a county is given a number that uniquely identifies them. A computer is used to select 500 of these numbers at random. The 500 voters identified by the computer are interviewed for a study. Which type of sampling was used?
systematic
random
cluster
convenience

Math

StatisticsOne year Alex had the lowest ERA (earned-run average, mean number of runs yielded per nine innings pitched) of any male pitcher at his school, with an ERA of 3.29. Also, Sally had the lowest ERA of any female pitcher at the school with an ERA of 2.68. For the males, the mean ERA was 4.047 and the standard deviation was 0.993. For the females, the mean ERA was 4.397 and the standard deviation was 0.626. Find their respective z-scores. Which player had the better year relative to their peers, Alex or Sally? (Note: In general, the lower the ERA, the better the pitcher.)

Math

StatisticsCarter invested $3,900 in an account paying an interest rate of 3.9% compounded daily. Assuming no deposits or withdrawals are made, how much money, to the nearest hundred dollars, would be in the account after 5 years?

Math

StatisticsHeights of AHS Girls basketball team players are approximately normally distributed with a mean of 70 inches and a standard deviation of 2.5. If there were 175 players, how many had a height between 71 and 74 inches?

Math

StatisticsDescribe the sampling distribution of p. Assume the size of the population is 20,000.
n = 600, p=0.6
Choose the phrase that best describes the shape of the sampling distribution of p below.
A. Approximately normal because n≤0.05N and np(1-p)<10.
B. Not normal because n≤0.05N and np(1-p)≥10.
C. Not normal because n≤0.05N and np(1-p)<10.
D. Approximately normal because n≤0.05N and np(1-p)≥10.

Math

StatisticsSuppose a simple random sample of size n = 81 is obtained from a population that is skewed right with µ=73 and σ=9.
(a) Describe the sampling distribution of x.
(b) What is P (x>74.1)?
(c) What is P (x≤70.55) ?
(d) What is P (72.15<x<74.85)?