# Statistics

A confidence interval for a population mean has a margin of error of 3.1.
a)Determine the length of the confidence interval.
b)If the sample mean is 56.7, obtain the confidence interval.

1. 👍
2. 👎
3. 👁
1. a)

± 3.1

b)

56.7 - 3.1 = 53.6
56.7 + 3.1 = 59.8

Interval is 53.6 to 59.8

1. 👍
2. 👎
2. the population of 1500 construction truck has load distributed normally with the mean of 6 tons and the standard deviation of 1 ton. Find the probability that its load is greater than 7?

1. 👍
2. 👎

## Similar Questions

1. ### statistics

what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5. a. 25 and 1.25 b. 5 and 5 c. 25

2. ### Statistics

Find the margin of error for a 95% confidence interval for estimating the population mean when the sample standard deviation equals 100, with a sample size of (i) 400, (ii) 1600. What is the effect of the sample size? (b) Find the

3. ### Statistics

Which of the following statements correctly interprets a 95% confidence interval on a population mean? a. It is a single point estimate b. Used to quantify the certainty of the sample standard deviation c. A 99% confidence

4. ### Statistics

The monthly incomes from a random sample of workers in a factory are shown below. Monthly Income (In \$1,000) 4.0 5.0 7.0 4.0 6.0 6.0 7.0 9.0 a. Compute the standard error of the mean (in dollars). b. Compute the margin of error

1. ### Statistics

Exercise 8.92 Tony's Pizza guarantees all pizza deliveries within 30 minutes of the placement of orders. An agency wants to estimate the proportion of all pizzas delivered within 30 minutes by Tony's. What is the most conservative

2. ### statistics

How large a sample should be selected to provide a 95% confidence interval with a margin of error of 10 (to the nearest whole number)? Assume that the population standard deviation is 40.

3. ### ap statistics

You are sampling from a population with a known standard deviation of 20 and want to construct a 95% confidence interval for the mean with a margin of error of no more than 4. What is the smallest sample size that will produce

4. ### statistics

A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is 15. a) Compute the 95 % confidence interval for the population mean. b) Assume that the same sample mean was obtained from a

1. ### Statistics

Direct mail advertisers send solicitations (that is "junk mail") to thousands of potential customers in the hope that some will buy the company's products. The response rate is usually quite low. Suppose a company wants to test

2. ### Statistics

A sample of 11 observations taken from a normally distributed population produced the following data. −7.1 10.3 8.7 −3.6 −6.0 −7.5 5.2 3.7 9.8 −4.4 6.4 a) What is the point estimate of μ? b) Make a 95% confidence

3. ### statistics (7)

The average cost per night of a hotel room in New York City is \$273 (SmartMoney, March 2009). Assume this estimate is based on a sample of 45 hotels and that the sample standard deviation is \$65. a. With 95% confidence, what is

4. ### Statistics

The standard deviation for a population is σ = 15.3. A sample of 36 observations selected from this population gave a mean equal to 74.8. a) Make a 90% confidence interval for μ b) Construct a 95% confidence interval for μ. c)