Developing confidence intervals

Assignment Help Basic Statistics
Reference no: EM13104379

1. A car rental office checks out an average of 30 cars per day with a standard deviation of 8 cars. If a sample of 25 days of operation is selected and the sample mean is computed. What is the value for the standard error of the mean? What is the probability that the sample mean for the 25 days will be within 27 and 32 cars?

2. In an effort to estimate the mean annual amount spent per customer for groceries at a particular supermarket, data were collected for a sample of 100 households. The sample showed an average amount of $8,000. If the population standard deviation is $500. Develop an 80% then a 85% confidence interval estimate of the population mean annual amount spent. If the data were collected for a sample of 50 households rather than 100, develop an 85% confidence interval estimate of the population mean annual amount spent, assuming the population has a normal probability distribution

Reference no: EM13104379

Questions Cloud

Computing confidence intervals : Bob Nale is the owner of Nale's Quick Fill. Bob would like to estimate the mean number of gallons of gasoline sold to his customers.
Find the normal force on the truck to the highway surface : A 1128 kg car and a 2210 kg pickup truck approach a curve on the expressway that has a radius of 272 m. A) At what angle should the highway engineer bank this curve so that vehicles traveling at 72.9 can safely round it regardless of the condition..
Find a significant increase in the proportion of items : If they find a significant increase in the proportion of items that must be rejected, they will halt the assembly process until the problem can be identified and repaired.
Average scores on golf course : A sample of 84 golfers showed that their average score on a particular golf course was 89.05 with a standard deviation of 3.47.
Developing confidence intervals : A car rental office checks out an average of 30 cars per day with a standard deviation of 8 cars. If a sample of 25 days of operation is selected and the sample mean is computed.
How far is it to the horizon : A person is standing at the edge of the water and looking out at the ocean (see figure). The height of the person's eyes above the water is h = 1.8 m, and the radius of the Earth is R = 6.38 x 106 m. (a) How far is it to the horizon? In other word..
Creating material requirement plan : The MPS for product A calls for 100 units to be completed in week 4 and 200 units in week 7 (the lead time is 1 week). Spare part demand for Item B is 10 units per week.
Point estimate of the population mean : The 2006 General Social Survey asked, "what do you think is the ideal number of children for a family to have?" The 1097 females who responded had a median of 2, mean of 3.16, and a standard deviation of 1.91.
Proportion of adults planning on buying car : A marketing research firm wishes to estimate the proportion of adults who are planning to buy a new car in the next 6 months. A simple random sample of 100 adults led to 22 who were planning to buy a new car in the next 6 months.

Reviews

Write a Review

Basic Statistics Questions & Answers

  Null hypothesis that all population means are equal

Will you reject your null hypothesis that all population means are equal or will you not reject? Choose the best answer from the options below.

  Discuss validity of central limit theorem

Critically discuss the Central Limit Theorem? How large should the sample size be if the underlying distribution of the population values are:

  Sat scores and central limit theorem

SAT Scores and the Central Limit Theorem. Assume that SAT scores are normally distributed with a mean of 500 and a standard deviation of 100.

  Mean of the data represented in this stemplot

Consider the following stemplot.  The mean of the data represented in this stemplot ?

  Probabilities of normal distribution

A survey for Hotels asked respondents "When traveling internationally, do you generally venture out on your own to experience culture, or stick with your tour group and itineraries?" The survey found that 23% of the respondents stick with their t..

  Relationship between height and doing gymnastics

Based on a study of heights of men and women who do gymnastics, a researcher concludes that the exercise from playing gymnastics causes people to become shorter. Do you agree with this conclusion?

  Smoking depends on the age category

Test at the 5% level whether the incidence of smoking depends on the age category

  Screening test for a rare disease

A pharmaceutical company has developed a screening test for a rare disease that afflicted 2% of the population. Unfortunately, the reliability of this test is only 80%, which means that 20% of the tested will get a false positive.

  Calculation-high-speed internet access

A researcher wishes to estimate with 99% confidence, the proportion of adults who have high-speed Internet access. Her estimate must be accurate within 2% of the true proportion.

  Lognormal distribution with a mean problem

Following a lognormal distribution with a mean of 3000 rpm and std deviation of 0.87, what if the boss want a 5% chance of HW failure before selling, how often would I have to replace this hardware ?

  Question on probability with replacement

3 voters are randomly selected (with replacement) from a group of 1,500 people. The group is known to be 20% republican. What is the probability that all of them are republicans?

  Estimating the probability with the given data

A certain airplane has 2 independent alternators to provide electrical power. The probability that a given alternator will fail on a 1 hour flight is 0.02. What is the probability that (a) both will fail? (b) Neither will fail? (c) One or the othe..

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd