# 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. 👍 0
2. 👎 0
3. 👁 202
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. 👍 0
2. 👎 0
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. 👍 0
2. 👎 0
posted by fara

## Similar Questions

1. ### STATISTIC

A study based on a sample of size 25 reported a mean of 94 with a margin of error of 15 for 95% confidence (a) Give the 95% confidence interval. (__________,________) (b) If you wanted 99% confidence for the same study, would your

asked by YOMO on May 28, 2017
2. ### Algebra 2: Prob and Stats

A survey of 480 high school students found that 37% had a pet. Find the margin of error. Round to the nearest percent. Use the margin of error to find an interval that is likely to contain the true population proportion. * margin

asked by Skye on May 24, 2010
3. ### math

The new Twinkle bulb is being developed to last more than 1000 hours. A random sample of 100 of these new bulbs is selected from the production line. It was found that 48 lasted more than 1000 hours. Find the point estimate for

asked by Heaven on April 17, 2011
4. ### STATISTICS

Determine the point estimate of the population mean and margin of error for the confidence interval. Lower bound is 15, upper bound is 27. A)The point estimate of the population mean is ________. B) The margin for error for the

asked by Megan on May 5, 2013
5. ### Statistics

In a poll of voters in a certain city, 32% said that they backed a bill which would limit growth and development in their city. The margin of error was reported as 1.7% with 90% confidence. Determine the bounds for the confidence

asked by Nick on October 27, 2013
6. ### statistics

In a poll of voters in a certain city, 32% said that they backed a bill which would limit growth and development in their city. The margin of error was reported as 1.7% with 90% confidence. Determine the bounds for the confidence

asked by debbie on October 23, 2011
7. ### Statistics

An opinion poll asks a random sample of 100 college seniors how they view their job prospects. In all, 53 say "Good." The 95% confidence interval has a margin of error of 9.9%. The sample used actually included 130 college seniors

asked by Samantha on November 11, 2013
8. ### Statistics

Thirty-three small communities in Connecticut (population near 10,000 each) gave an average of x = 138.5 reported cases of larceny per year. Assume that σ is known to be 42.9 cases per year. (a) Find a 90% confidence interval for

asked by Amy on December 3, 2016
9. ### business statistics

1. The average life expectancy of people around the world is 71.30 years with a population standard deviation of 8.00 years. I take a sample of 50 countries now and find that the average life expectancy is 74.37 years. Suppose

asked by amanda on November 7, 2016
10. ### stat

7. A researcher selects a random sample. A 90% confidence interval for a population mean  A) is an interval with margin of error ± 90%. B) has the property that if we repeatedly selected our random sample in exactly the same

asked by Anonymous on December 5, 2010

More Similar Questions