Math Answers

Find 90% confidence interval for the mean of normal distribution if a sample of size 7 gave the values 9,16,10,14,8,13,14

. The radioactive isotope carbon-10 has a half-life of 20 seconds.

a. How much time is required so that only 1/16 of the original amount remains?

b. Find the rate of decay at this time.

Keith’s Florists has 15 delivery trucks, used mainly to deliver flowers and flower arrangements in the Greenville, South Carolina, area. Of these 15 trucks, 6 have

brake problems. A sample of five trucks is randomly selected. What is the probability that two of those tested have defective brakes?

A certain population is composed of the numbers 4, 5, 6 and 7. What is the mean of the sampling distribution of the sample mean if each sample contains two elements?

The mean of the sample means in a sampling distribution is 2.6. What is the mean of the population from which the scores are sampled?

How many possible samples of size n = 3 can be drawn from a population of size 10? *

A town has a population of 17000 and grows at 4% every year. What will be the population after 12 years, to the nearest whole number?

Determine which of the following is the solution set of the linear equations below.

3x − y + z = 2

2x − z = 2

An element with mass 820 grams decays by 26.8% per minute. How much of the element is remaining after 18 minutes, to the nearest 10th of a gram?

The head of the Philippine University (PU) observes a decline on the alcoholic expenditures of learners from a monthly expenditure of Php 350 pesos in the previous year. To check on this, he randomly selected 10 PU learners who drink alcoholic beverages and asked the amount, in pesos, that they usually spend on alcoholic beverages in a month. It is known that the usual amount spent on alcoholic beverages by learners who drink alcoholic beverages follows the normal distribution with standard deviation of Php 10. The data collected are: 400, 235, 200, 250, 200, 300, 500, 430, 420, and 220.

Construct and interpret a 95% confidence interval for the true mean amount spent by the learners on alcoholic beverages.

Find a 90% confidence interval for the true mean amount spent by the learners on alcoholic beverages.