confidence intervals

A television channel conducted a survey of 90 adults and found that 54 regularly watch television at home. Find a 90% confidence interval of the true proportion of adults who watch television regularly. => 59.6% < p < 60.4% or 50% < p < 60% or 54.8% < p < 65.2%..

95% confidence interval of a population mean with a sample size of 18 was found out as 6.17 < μ < 6.99. Another study calculated the 95% confidence interval as 5.71 < μ < 7.46. Which among the following can be the possible sample size of the..

The average hemoglobin levels of 20 students was measured as 14.2 grams per 100 ml. They are 99% confident that the true mean is between 12.4 and 15.6. Find 95% confidence interval for the average hemoglobin level(μ). => 13 < μ < 16 or 12.55 < μ < ..

A survey revealed that the extent to which the proportion of dental students use the internet to retrieve information for dental topics is 32%. How many dental students should be surveyed to estimate the true proportion of students who use internet with 99% confidence interval 4..

A retail garment shop receives a shipment of trousers, with a standard length of 49.0 in. and a standard deviation of 1.0 inch. A random sample of 32 trousers had a mean length of 48.8 in. Find the 95% confidence interval. => The interval between 48.65 and 49.35 or The..

The manager of a company wishes to estimate the average age of the present employees. From the past records, the standard deviation is found to be 8 years. A sample of 100 employees are selected and the mean is found to be 42.8 years. Find the 99% confidence interval of the popu..

A management firm wants to estimate the mean cost of repairing the apartments that are vacated by tenants. A sample of 18 vacated apartments resulted in a mean repair cost of $109 with a standard deviation of $12. Find the 90% confidence interval to estimate the mean repair cost..

The average intake of added sugars by a person is observed to be 68 gm/day for 10 days with a sample standard deviation of 2.86 grams. Find the 99% confidence interval of the true mean. => 65.1 < μ < 70.9 or 64 < μ < 01 or 67 < μ < 69 or 65 < μ &..

A survey of software engineers having more than ten years experience finds the average salary to be $120,000. If the standard deviation for the sample of 40 software engineers was $12,000, construct a 99% confidence interval of the mean(μ) for all engineers. => 118,102.63 <..

The university authorities wanted to estimate the average age of the students in their university by taking a random sample of 25 students. The standard deviation was found to be 3 years. Find the 95% confidence interval for the variance (σ 2 ) and standard deviation (&sig..