# Tag: interval estimation

#### Solved: A survey of 120 female freshman showed that 18 did not wish to work after marriage. Find the 95% confidence interval

A survey of 120 female freshman showed that 18 did not wish to work after marriage. Find the 95% confidence interval of the true proportion of females who do not…

#### Solved (Free): In a study conducted for the effectiveness of drug A on a certain disease, 60 randomly selected patients with this disease were given medication

In a study conducted for the effectiveness of drug A on a certain disease, 60 randomly selected patients with this disease were given medication and 36 patients recovered. Calculate the…

#### Solved (Free): A survey was conducted on a random sample of 1,000 Baltimore residents. Residents were asked whether they have health insurance. 650 individuals surveyed

A survey was conducted on a random sample of 1,000 Baltimore residents. Residents were asked whether they have health insurance. 650 individuals surveyed said they do have health insurance, and…

#### Solved (Free): The American Cancer Society wants to estimate the proportion of high school seniors who smokes regularly. In a random sample of

The American Cancer Society wants to estimate the proportion of high school seniors who smokes regularly. In a random sample of 1,000 seniors, 200 smoke regularly. Construct 90% confidence interval.…

#### Solved (Free): A random sample of 100 light bulbs has a mean lifetime of 3000 hours. Assume that the population standard deviation of the lifetime is 500

A random sample of 100 light bulbs has a mean lifetime of 3000 hours. Assume that the population standard deviation of the lifetime is 500 hours. Construct a 95% confidence…

#### Solved (Free): A trucking firm has a large inventory of spare parts that have been in storage for a long time. It knows that some proportion of these spare parts will have deteriorated to the point where they are no longer usable

A trucking firm has a large inventory of spare parts that have been in storage for a long time. It knows that some proportion of these spare parts will have…

#### Solved (Free): An admissions officer has determined that the population of applicants to the MBA program has undergraduate GPA that are approximately

An admissions officer has determined that the population of applicants to the MBA program has undergraduate GPA' that are approximately normally distributed with standard deviation 0.45. A random sample of…

#### Solved (Free): Six soil samples taken from a particular region were subjected to chemical analysis to determine the pH of each sample

Six soil samples taken from a particular region were subjected to chemical analysis to determine the pH of each sample, yielding a sample mean pH of 5.9 and a sample…

#### Solved (Free): The true proportion of defective memory chips produced by a certain company is p. Suppose a random sample of 400 memory chips are tested

The true proportion of defective memory chips produced by a certain company is p. Suppose a random sample of 400 memory chips are tested and 10 of them are found…

#### Solved (Free): In an investigation of pregnancy induced hypertension, one group of women with this disorder was treated with low dose aspirin, and the second group was given a placebo

In an investigation of pregnancy induced hypertension, one group of women with this disorder was treated with low dose aspirin, and the second group was given a placebo. A sample…